SB 945 
.S2 R5 
Copy 1 



State of HI)obc Jslanb Qn^ |Pl•ol1i^cnce ^plantations. 



THE SAN JOSE SCALE 



( Aspidiotus pernieiosus, Comst.) 



METHODS OF TREATMENT. 



A. E. STENE 




. FiQ. 1.— Female San Jose Scale. After Atwood. See page 24. 

Joint Bulletin of the State Board of Agriculture and Extension 
Department of the Rhode Island College of Agriculture 
and Mechanic Arts. 



1908. 




s.%"°i* 



ERRATA. 



In the second paragraph on page 13, line five should read as 
follows : ^^have fallen in the autumn, or just before they come 
.out in the spring." 

Note further discussion of this topic on page 64, and re- 
member that the principal spraying for the San Jos6 Scale is 
given when the trees are dormant. Summer spraying with ker- 
osene emulsion is sometimes given, but only to check the scale 
until eflfective winter treatment can be given. 



state of HI)obc Islanb anb prouibeiuc plantations. 

THE SAN JOSE SCALE 

(Aspidiotus perniciosus, Comst.) 



AND 



METHODS OF TREATMENT. 



A. E. STENE. 




Fig. 1.— Female San Jose Scale. After Atwood. See page 24. 

Joint Bulletin of the State Board of Agriculture and Extension 
Department of the Rhode Island College of Agriculture 
and Mechanic Arts. 

1908. 






g^f 33 1908 



r-3y^^ 



PREFACE. 



This bulletin is written in response to a very urgent demand for 
information on the San Jos4 scale, as evinced by the hundreds of 
letters which come into the office of the Extension Department of 
the College every year with questions regarding this insidious fruTf 
pest and methods of destroying it or preventing its ravages. 

The bulletin is divided into two parts. The first part, in large 
type, is in the nature of a summary, and presents briefly the 
essentials in formulas and directions for treatment of the scale for 
quick perusal and for those who do not care for a further study of 
the subject. With each of the statements in the summary, page 
references are given to the second part of the bulletin. 

The second part of the bulletin takes up a fuller discussion with an 
endeavor to present a history and description of the scale and 
methods of dealing with it in the light of present knowledge and 
practice such as the up-to-date Twentieth Century farmer is demand- 
ing. 

The bulletin contains but little original material, except such 
general observations as have been made on the behavior of the scale 
under local conditions and the tabulation of losses as shown by in- 
formation obtained through the circular sent out the past autumn 
to the names on the mailing list of the Rhode Island Experiment 
Station. 

An endeavor has been made to present the gist of information 
which seems, in the opinion of the writer, essential to a fairly com- 
plete knowledge of the scale and methods of treatment, but un- 
doubtedly much has been left out, and if anyone wishes to pursue 
the subject further, he can refer to the following books and publica- 
tions, from which the writer's information i^ largely drawn: 



4 THE SAN JOSE SCALE. 

Economic Entomolog}^, by Dr. John B. Smith, pubhshed by Lip- 
pincott. 

Fumigation Methods, by Willis G. Johnson, published by Orange 
Judd Co. 

Spraying of Plants, by Lodeman, published by the Macmillan Co. 

Bulletins of the N. Y. State Museum at Albany, by E. P. Felt. 

Bulletins by Dr. Howard and Dr. Marlatt and others of the De- 
partment of Agriculture at Washington. 

Bulletins of various experiment stations in the United States, 
but principally those of New York, Delaware, Massachusetts, Con- 
necticut, California, and Washington; also articles from the Rural 
New Yorker, Country Gentleman, and the New England Homestead. 

ACKNOWLEDGMENT. 

The writer is greatly indebted to the Bureau of Entomology, De- 
partment of Agriculture, at Washington, for co-operation in securing 
estimates of damage done by the scale; to the Rhode Island Ex- 
periment Station for the use of mailing machine in sending out cir- 
cular letters ; to the Federal Department of Agriculture and various 
experiment stations, and manufacturers of spray apparatus, for use 
of cuts, full credit of which is given elsewhere; and to the following 
persons for submitting estimates of value of fruit trees: L. G. K. 
Clarner, Arnold's Mills, R. I.; Cyrus Miller, Haydenville, Mass.; Prof. 
Craig, Cornell University: Prof. U. P. Hedrick, New York Experi- 
ment Station, Geneva; Prof. William Stuart, Vermont Experiment 
Station ; and Geo. T. Powell, Ghent, N. Y. 



CONTEXTS. 



Preface 3 

Contents 5 

Summary 9 

Introduction 14 

Popular Fallacies Regarding Insects and Their Control 16 

General History of the San Jose Scale 20 

History in Rhode Island 21 

Methods of Detecting the Scale 22 

Life History 23 

Description of the San Jose Scale 25 

Host Plants 27 

Natural Enemies of the San Jose Scale 32 

Means of Distribution of the Scale 34 

Losses Due to the Scale in Rhode Island 35 

Status of Fruit-growing as Affected by the Scale 38 

Future Prospects 40 

Chances of Saving Trees Badly Infested 41 

Does it Pay to Spray 41 

Present Means of Controlling the San Jose Scale 42 

General Orchard Treatment 42 

Spraying 44 

Brief General History of Spraying for the Scale 44 

The Lime-Sulfur Wash 46 

Formula for Lime-sulfur Wash Generally Recommended at 

the Present Time 48 

Ingredients of the Lime-sulfur Wash 49 

Apparatus for Preparing the Lime-sulfur Wash 51 

Chemical Composition 52 

Other Lime-sulfur Remedies 55 

Remedies from Petroleum 56 

Kerosene Limoid Mixture 57 

Miscible Oils 58 

Proprietary Remedies from Petroleum 60 



6 THE SAN JOSE SCALE. 

Comparative Value of the Lime-sulfur and Miscible Oils 60 

Miscellaneous Spray Solutions for the San Jose Scale . . 61 

Whale Oil Soap 61 

Resin Wash 62 

A New Wash Proposed by the U. S. Dept. of Agriculture. ... 62 

Comparative Cost of Spray Solutions 63- 

The Time of the Year to Spray 64 

Methods of Applying Spray Remedies 64 

Spraying Apparatus 65 

Fumigation with Hydrocyanic-acid Gas 74 

Orchard Fumigation 76 

Fumigation of Nursery Stock 77 

Apparatus, Chemicals, and Methods of Fumigating Nursery 

Stock 78 

The Fumigation House 80 

Fumigation of Peach and Nectarine Houses for the San Jose Scale . 83 

Directions for Fumigating Peach and Nectarine Houses . . 84 

The Operation 86 

Dipping Nursery Stock 87 

Additional Notes and Explanations Regarding Illustrations — 

Acknowledgment for use of Cuts 89 

Notes 89 



LIST OF CUTS. 



Page Reference 

Figures. of Cut. Page. 

1. Female San Jose Scale 1 24 

2. San Jose Scale on Twig 9 23 

3. Male San Jose Scale Insect 20 26 

4. Magnifying Glass 22 23 

5. Underside of Female showing Sucking Tube 24 26 

6. Development of the Scale 25 23 

7. Scale of Male San Jose 25 26 

8. Cut showing Characteristic form of Annal Plate of Female, as 

seen under the Microscope 26 

9. Microweisia misella Preying on San Jose Scale 32 33 

10. Strainer for Straining Spray Solutions into Tank 51 

11. Compressed Air Knapsack Sprayer 66 66 

12. Large Tank with Agitator, for Large Hand or Gasoline Pump. 67 

13. Type of Double Acting Tank Pump 67 67 

14. Bamboo Extension Pipe 68 72 

15. Short Extension Pipe for Use with Bucket or Knapsack Spray- 

ers 68 72 

16. " Y " for Attaching Two Nozzles to One Lead of Hose 68 73 

17. "Mistry"Vermorel Nozzle 68 72 

18. "Mistry Junior" Nozzle 68 

19. " Demorel" Nozzle 68 73 

20. Boiling Lime-sulfur with Steam 69 51 

21. Boiling Lime-sulfur with Kettles 70 51 

22. Home-made Strainers 71 

23. A Recent Form of Vermorel Nozzle 72 73 

24. A Type of Vermorel Nozzle without Plunger 72 

25. Battery of "Spramotor" Vermorel Nozzles 73 73 

26. \ / 85 . . 
f Cuts Illustrating Method of Ascertaining Contents of \ 

27. y \ -"^ 85 . . 
V Fumigation Houses J 

28. / V 86 . . 

29. Dipping Nursery Stock, Roots and Body 87 88 

30. Dipping Nursery Stock, Body only 87 88 



8 THE SAN JOSE SCALE. 

Reference 

Plates. Page. 
I. Frontispiece, Part of Large Orchard Destroyed by Scale. East 

Providence 

II. San Jose Scale on Kieffer Pear, etc 

III. Fig. 1. Picture of Scale on Bark 25 

Fig. 2. Fumigation Utensils 78 

IV. Good Culture in Apple and Pear Orchards 42-43, 90 

V. Mossy Top of Apple Tree; A Capital Place for Scale 91 

VI. High and Low Training of Apple Trees 42-43. 91 

VII. Tall Pear Tree on Which the Scale must be fought at a Great 

Disadvantage 42-43, 91 

VIII. Thorough Pruning and Spraying for the San Jose Scale 43, 91 

IX. A Well-Sprayed Orchard 

X. Peach Tree badly Infested with the San Jose Scale 

XI. Small Portable Barrel Pump 67 

XII. Fig. 1. Barrel Pump Showing Agitator 67 

Fig. 2. Bucket Pump 67 

Fig. 3. Gasoline Power Sprayer 68 

XIII. Fig. 1. Vice-Admiral 67 

Fig. 2. Knapsack Spray Pump 67 

Fig. 3. Tower on Tank ; 73 

Fig. 4. Tower on Tank; Machinery in Operation 73 

XIV. Fig. 1. Invincible Mounted Sprayer 67 

Fig. 2, Invincible Mounted Sprayer, Gasolene Power 

XV. Niagara Gas Sprayer with Tower 73 

XVI. Fig. 1. Plant for Preparing Lime-sulfur Wash with Steam 51 

Fig. 2. Cooking Lime-sulfur Wash with Steam 51 

XVII. Hexagonal Fumigator for Trees 76 

XVIII. Box for Fumigating Nursery Stock 81-82 

XIX. Fumigation House for Nurseries 80-81 




Fig. 2.— San Jose scale on twig, enlarged five times. 
After Atwood. 



SUMMARY. 



Injurious insects take an enormous toll from the pro- 
ducts of the farm, garden, and forest. It amounts to 
from six to eight hundred millions of dollars a year. 
Pages 14 to 16. 

Erroneous ideas regarding the character of injurious 
insects and plant diseases lead to a great deal of useless 
expense and labor in the attempts to control them. 
Pages 16 to 19. 

The San Jose scale was introduced from China into 
the San Jose Valley of California sometime previous to 
1873. In 1887 it was found in the East, and since that 



10 THE SAN JOSE SCALE. 

time it has spread, principally through the transportation 
of nursery stock, over a large part of the United States. 
Pages 20 and 21. 

The first intimation of its presence in Rhode Island 
was gotten in 1897. It is probable that it was intro- 
duced into the State a few years previous to that time. 
It is now found in ever}^ town in the State, and in a 
large majority of the orchards. Pages 21 and 22. 

When only a few of the San Jose scale are present, the 
insect is difficult to detect. When a tree or shrub be- 
comes thoroughly infested, the scale forms a grayish, 
scurfy coating on the bark. On rubbing the bark vigor- 
ously, a yellowish liquid appears, due to the crushing of 
the insects underneath the scale. On young, green 
wood, and on light or green-colored fruit, a reddish dis- 
coloration can be seen around each scale. A small, 
low-priced magnifying glass is of great aid in detecting the 
insect. Pages 22 and 23. 

The San Jose scale survives the winter in the larval 
stage, and matures in the early spring. Unlike most 
of the insects that we are acquainted with, the San Jose 
scale does not lay eggs, but produces its young alive. 
The period of bearing young extends, for each female, 
over five or six weeks, and a total of from three to four 
hundred are produced. The young larva remains active 
for about a day and a half, after which it settles down 
and begins to secrete over itself the scale covering. 
The females never move again, but the males when 
mature appear as minute, two-winged, fly-like insects. 
The San Jose scale insect matures in about forty-five 



THE SAN JOSE SCALE. 11 

days from birth, and we have here in the North from 
three to four generations. Pages 23 to 26. 

The host plants of the San Jose scale include a large 
nimiber of the trees and shrubs usually grown in nur- 
series. Pages 27 to 31. 

The enemies of the San Jose scale include a number of 
very minute, parasitic-insect enemies, and the well-known 
ladybird beetles. Pages 32 to 34. 

The San Jose scale is distributed largely by means of 
nursery stock. For short distances it may be carried 
by the wind, insects, birds, and even higher animals. 
It may spread from tree to tree by interlacing branches. 
Page 34. 

The loss due to the scale in the State of Rhode Island 
amounts, at a conservative estimate, to over two hundred 
thousand dollars. Pages 35 to 38. 

The San Jose scale is changing the fruit-growing of 
the State. Small growers are becoming discouraged, 
and only those who are taking up a fight against the scale 
in an energetic manner have faith in the future of fruit- 
growing. Pages 38 to 40. 

Fruit-growing is gravitating into the hands of special- 
ists. A higher class of fruit and better prices will be the 
rule in the future. Page 40. 

The chances of saving a tree badly infested with the 
San Jose scale depend upon its vitality primarily, but 
also on the determination of the grower to continue 
fighting the scale. Page 41. 

The law of supply and demand will so regulate the 



12 THE SAN JOSE SCALE. 

price of fruit that it will cover the* additional cost of 
spraying. Pages 41 and 42. 

The present means of controlling the San Jose scale 
may be divided into two classes: First, preventive or 
general orchard treatment. Plant stock free from scale; 
keep it in a thrifty condition; and plant and prune so 
as to make the labor of subsequent spraying economical. 
Pages 42 to 44. Second, spraying. Spray thoroughly in 
early spring or late fall with an effective solution. Trees 
badly infested should be spraj^ed both spring and fall. 
The standard remedy to-day is the lime-sulfur wash, 
made up as follows: 

Lime, fresh, unslaked 15-20 lbs. 

Sulfur 15 lbs. 

Water 50 gals. 

Slake the lime with hot water enough to keep it well 
covered. Make the sulfur into a thin paste with a 
small quantity of hot water, and add to the lime while 
slaking. Stir thoroughly, and when slaking ceases, add 
water to make 20 or 25 gallons. Boil from 45 minutes to 
one hour in a kettle, or by means of steam. Strain through 
a wire sieve of 20 meshes to the inch into spray barrel 
or tank, and add water to make 50 gallons. Apply at 
once. Pages 44 to 56. 

Excellent remedies are obtained from petroleum. 
Miscible, or so-called ''Soluble" oils, either home-made 
or some of the well-prepared proprietary brands, are ef- 
fective and can be recommended for those who can not 
use the home-made lime-sulfur wash. Pages 56 to 60. 



THE SAN JOSE SCALE. 13 

A discussion of the comparative value of the lime-sul- 
fur and miscible oils is given on pages 60 and 61, and a 
few other spray solutions used for the San Jose scale are 
mentioned on pages 61 and 62. 

The time of the year to spray depends a little on the 
extent of the infestation and on the solution used, but 
principally on the convenience of the orchardist. Gen- 
erally speaking, it should be given just after the leaves 
have fallen in the autumn, or just after they come out in 
the spring. (The one absolutely important considera- 
tion in applying a spray remedy against the scale is 
thoroughness.) 

A good spray outfit, suitable to the kind and amount 
of spraying to be done should be secured. The essentials 
are a good pump, sufficient length of hose, an extension 
rod, and a good nozzle of the Vermorel type. Pages 65 
to 73. 

Fumigation with hydrocyanic-acid gas is useful under 
some conditions. As an orchard remedy it is of little 
value in the East.. Pages 74 to 77. 

As a preventive of distribution of the scale through 
nursery stock, fumigation is worthy of careful considera- 
tion. Pages 77 to 83. 

As a remedy for the San Jose scale in greenhouses, 
hydrocyanic-acid gas is practically a specific. Pages 83 
to 87. 

The dipping of nursery stock is being recommended 
as a substitute for fumigation, and is worthy of trial. 
Pages 87 and 88. 



INTRODUCTION. 



During the last few years a careful study of injurious insects has 
brought out the not very pleasant, yet interesting, fact that they take 
an enormous toll from the annual production of crops in the United 
States. Dr. Marlatt, in a recent paper in one of the yearbooks of 
the Department of Agriculture, estimated that the annual loss to 
growing farm crops alone, due to insect depredation, amounts to 
about 10 per cent, of the total value of these crops. For the year 
in which the paper was written, the total loss due to insect injury 
was about five hundred millions of dollars. If we add to this the 
loss to forest crops and products of all kinds in storage, there was 
for that year a grand total of between seven hundred and fifty and 
eight hundred millions of dollars. And yet this does not include the 
total loss due to insects, for we have learned that they enter into our 
interests in various ways which were not known or suspected until 
recent times. Take, for instance, the carrying of disease by insects 
which results in loss of health, productive capacity, and attendant 
expenses, to say nothing about the frequent loss of human life. 

The only reason why farmers have submitted to their part of the 
heavy tax without complaint, except when the enormous increase of 
some particular species of insect has caused an uncommonly large or 
total destruction of crops, is: first, that they have not always realized 
its enormity, the levy being generally made before the crop is har- 
vested and measured; second, the comparative familiarity with 
loss due to insects and the consequent indifference; and third, the 
idea that the loss is more or less inevitable and must be accepted as 
a matter of course. 

A study of our injurious insects has further revealed the fact that 



THE SAN JOSE SCALE. 15 

a large percentage of our worst pests are foreigners, and have gained 
entrance to our country through the avenues of transportation in one 
way or another. In a recent exhibition of the Department of Agri- 
culture at the World's Columbian Exposition, as described by Dr. 
Howard in the Yearbook for 1897, 602 different species of insects, 
171 of which were imported species, were shown as being more or 
less injurious to agricultural products. From this group were again 
separated out 73 which were especially injurious, and of these 30 
were native, 37 imported, and 6 of doubtful origin. Among the 
imported ones may be mentioned the San Jose scale, gypsy moth, 
brown-tail moth, elm-leaf beetle, codling moth, cabbage worm, cotton 
boll weevil, oyster-shell scale, pea weevil, buffalo moth, leopard 
moth, asparagus beetles, and Mediterranean flour moth. 

Once in this country and acclimated, which most of them become 
in a comparatively short time, they have found an abundant food 
supply and more or less freedom from the parasitic and predaceous 
enemies which harassed and kept them in check in their native 
habitats. Insects have enormous reproductive powers, and with 
the natural checks removed, these introduced pests have increased 
at an alarming rate in the case of some species, and have spread 
consternation in the ranks of many people who grow the crops on 
which these insects feed. 

It is well to remember that we have not as yet all the injurious in- 
sects of foreign countries which are liable to be imported. Dr. 
Howard, in the article already quoted, describes a number of in- 
jurious insects from Europe, Australia, West Indies, Mexico, and 
other countries, which are liable to be imported at any time, and 
which are injurious to species of fruit raised in the United 
States. 

A national quarantine law similar to that now carried out by the 
State of California, through which a thorough inspection can be made 
of all plants and material which are liable to bring these insects into 
our country, is an immediate necessity. It has been recommended 
to Congress on several occasions by Dr. Howard and others, but so 



16 THE SAN JOSE SCALE. 

far no steps have been taken to pass such a law. The only thing 
that can be done at the present time is for the inspectors of the dif- 
ferent maritime States to keep a sharp lookout for importations of 
plants; and nurserymen and others who order from foreign countries 
can help materially by notifying the inspectors of the arrival of con- 
signments of such plants in order that inspections may be made if' 
necessary. 

Many of the introduced insect pests just mentioned have created 
great havoc locally in many parts of the country, but there is per- 
haps no insect which has gained such wide-spread distribution 
throughout the whole country, and caused such large losses generally, 
as the San Jos6 scale. On account of its wide dissemination and 
detrimental work, there is an enormous amount of published infor- 
mation available regarding the pest, but much of this literature is 
of little or no interest to the average grower. Nevertheless, in order 
to intelligently take up the problem of dealing with the insect, he 
should have a thorough knowledge of its life history and the various 
methods of fighting it, together with the reasons for the various 
recommendations. This part of the bulletin will, therefore, be de- 
voted to presenting this information as briefly and plainly as pos- 
sible. There is also a little information in regard to the history of 
the San Jose scale in this country; the struggles which have been 
going on against it in the different sections, and especially in this 
State; its present status and the prospects for the future, which will 
be of some value in itself to the average citizen interested in the 
presence of the scale as an economic problem, and also as throwing 
light on the importance to the agriculturist of being on the lookout 
to prevent the introduction and dissemination of other pests which, 
fortunately, have not as yet reached our country. 

Popular Fallacies Regarding Insects and their Control. 

Not knowing the life history or character of insects, many suppose 
that a spray good for one kind will also be efficient for others. Hav- 
ing learned that certain stomach poisons, such as, Paris green, ar- 



THE SAN JOSE SCALE. 17 

senate of lead, etc., are effective against potato bugs, they are sur- 
prised to find out that these are of absolutely no use for the San Jose 
scale. Still others show less knowledge of the principles of spraying 
in believing that any spray solution, as for example, Bordeaux mix- 
ture, should be good for the whole category of plant ills. It can not 
be emphasized too strongly that insects must be treated in a different 
way from plant diseases, and also that the species of these two classes 
of plant enemies vary greatly in their habits and life history, and a 
thorough knowledge of each is necessary in order to work intelligently 
in destroying or controlling them. 

It is of special importance to the modern farmer to know 
that insects may be divided into two classes, according to 
the manner in which they take their food: 1. Those which 
chew the leaves or other parts of the plant. 2. Those which 
insert a beak or tube into the tissues of the plant and suck up its 
juices. Prominent examples of the former are various injurious 
beetles, such as, the potato and rose beetles, popularly termed 
"bugs," and their larvse, and the caterpillars of the various butter- 
flies and moths, such as, the cabbage butterfly, the mourning cloak 
butterfly, and the gypsy and brown-tail moths. As an example of 
the latter may be mentioned the true bugs, to which belong plant 
lice, scale insects, the squash bug, etc. The former can be quite 
readily reached in many cases with some form of stomach poison 
put upon the outside of the leaves or other parts of the plant on 
which they feed, but it is evident that the latter class, since they 
absorb all their food from the interior of the plant, can not be 
reached by any such application of poisons. It may also be added, 
although it is very much to be regretted that it should be neces- 
sary, that neither this class of insects nor any kind of an insect 
which feeds upon plant tissues can be discouraged or destroyed by 
any magical process of inserting or injecting chemicals into any 
part of the plant, or by spreading them in or on the soil for absorption 
by the roots. The reasons for this are self-evident on even casual 
reflection. The plant would be unable to take up any appreciable 



18 THE SAN JOSE SCALE. 

amount of such chemicals. If taken up, the distribution thereof 
would be extremely local and weakened by dilution with large 
quantities of sap; and finally, should such nostrums be absorbed 
in sufficient quantity to poison the insect, the plant itself would be 
poisoned and destroyed. 

Coming back to a more specific consideration of the San Jos6 scale, 
we frequently hear of other remedies and processes of treatment 
which are more rational but nevertheless faulty in their composition 
or application, or both. For example: Common whitewash is ap- 
plied by a great many to the trunk and branches of the trees with 
the mistaken idea that it is an efficient remedy against the scale. 
The application of this is faulty for two reasons: In the first place 
it is not sufficiently strong to destroy any but possibly the young 
^nd only partially protected scale; and secondly, because its appli- 
"Cation on the trunks and large branches only protects those parts of 
the tree, the infestation of which is in reality of much less importance 
than the infestation of the smaller branches and twigs. Another 
objection to this method — and it is true of the application of any 
:Solution, whatever it may be — is that no remedy against the San Jose 
;scale can be put on with a paint brush or wash rag, unless the tree 
IS very small or pruned back to the trunk and a few stubs of branches, 
without the application of so much labor that the cost of application 
will greatly exceed the value of the tree. The grower must pro- 
vide himself with adequate and up-to-date apparatus suited in size 
to the number of trees which he will have to spray. The Twentieth 
Century agriculture can not succeed with antiquated methods and 
appliances. 

Mechanical means, such as scraping the trunk and larger branches, 
are sometimes resorted to, but for reasons already given, such 
remedies are of little use. If the tree is an old one with very rough 
bark, scraping off the loose portions which may hide the scale under- 
neath is valuable as preparation for subsequent thorough spraying. 
The only mechanical remedy which is at all efficient is the appli- 
cation of a sharp axe to the trunk of the tree close to the ground. To 



THE SAN JOSE SCALE. 19 

those who can not or will not have their trees thoroughly treated, it 
is undoubtedly the only remedy when the trees have become thor- 
oughly infested, for so far, we have not come across a single case in 
the State where the scale, when once established, has ceased its work 
until after the tree has been destroyed, unless intelligently treated 
with some effective scale remedv. 



THE SAN JOSE SCALE. 

(Pronounced San Ho-say.) 
Aspidiotus perniciosus, Comst. 



General History. 

This insect was first discovered in this country in Cahfornia in 
1873, The term San Jose scale is derived from the valley of that 
name where it was first located. It must have been prevalent some- 
time previous to the year mentioned, as it was then well distributed 
in the section where it was found. 




Fio. 3.— Male San Jose scale insect, greatly enlarged, after Howard, 
U. S. Dept. of Agr., Bur. of Ento., Bui. 62. 

The first description of the insect was written by Professor Com- 
stock in 1880. In recognition of its capacity for serious mischief be 
called it Aspidiotus perniciosus. The Pernicious Scale has been sug- 



THE SAN JOSE SCALE. 21 

gested as a common name but has not been generally accepted, and 
it is doubtful if another name, "The Chinese Scale/' proposed by 
the Department of Agriculture will displace the one by which it has 
been known for so many years. 

There has been a great deal of speculation as to where this insect 
originated. It was successively reported as having been introduced 
from Chili, Hawaiian Islands, Australia, and Japan; but recent in- 
vestigations by Dr. Marlatt of Washington seem to prove quite con- 
clusively that the original home of the San Jose scale is in China. 

In the East the scale was first discovered in the grounds of Dr. C. 
H. Hedges of Charlotte ville, Virginia, in 1893. The infestation was 
investigated, and the introduction was quite definitely traced to two 
New Jersey nurseries, which in 1886 or 1887, in an endeaver to se- 
cure a curculio-proof plum, had imported a number of plum trees 
from the San Jose district in California. These nurseries, probably 
without knowing what a serious pest they were distributing, scattered 
it broadcast in various localities in the Eastern United States. It 
soon got into other nurseries, and at the time of its discovery in 
1893, as subsequent investigation proved, it had become established 
in a large number of different places in the various states. Since 
then, and until the inspection laws became generally enacted in the 
•different states, while some of the nurseries took pains to send out 
only clean stock, the scale was still further disseminated into almost 
every state in the Union by ignorant or irresponsible nurserymen 
and others dealing in shrubs and trees liable to be infested. 

Recent legislation has put a partial check upon the continued 
■distribution, but the scale has now been so far scattered that all 
hope of ever exterminating it has gone, and all that can be done is to 
•check its ravages and reduce the damage from it to a minimum. 

History in Rhode Island. 

It is difficult to trace definitely the history of the scale in Rhode 
Island. Professor Marlatt, in Bulletin 62 of the Bureau of Ento- 
mology, Department of Agriculture at Washington, states that 



22 THE SAN JOSE SCALE. 

up to 1898 no report of the presence of the scale had come from 
this State, In a bulletin by the State Board of Agriculture, written 
by Mr, Southwick in 1900, the author speaks of it as being of re- 
cent importation. It is probable, however, that it was known to 
be present as early as 1897, and to have been established sometime 
previous to this year. Professor Adams of the Rhode Island Col- 
lege states it as his recollection that the first report of the presence 
of the scale came to this institution from Newport in 1897, and that 
another was sent in soon thereafter from an estate near East Green- 
wich, Beginning with 1898 a large number of reports and also 
infested material were received at the college from various parts 
of the State, It was undoubtedly thoroughly established in some 
of the larger nurseries of the State at this time, as many growers 
are quite unanimous in their statements that trees which they pur- 
chased from certain nurseries near Providence from 1898 to 1900 
were destroyed two or three years later by what proved to be the San 
Jose scale. 

At the present time there is not a single town in the State but 
what is infested in one or more localities, and no plantations in 
which nursery stock has been set out within the last ten years are 
likely to be free from the pest. It is probable that four-fifths of 
the orchards of the State are more or less infested, and in many 
places the majority of the trees have been so badly injured as to 
necessitate their destruction. 

Methods of Detecting the Scale. 

When a tree or shrub first becomes infested and there are only a few 

scales present, detection is extremely 
difficult even for the experienced 
entomologist. To those inexperi- 
enced in the use of the magnifying 
glass, detection is more or less 

F.a.4.-Magnifying Glass. ^.^^^^^ ^^^.^ ^^^ ^^.^^ beCOmeS 

quite thoroughly infested, at least in places. Close observers will 




THE SAN JOSE SCALE. 23 

probably notice quite readily with their naked eyes the bright 
yellow little insects which crawl around throughout the summer- 
time and autumn until frosts set in. The light-colored scales about 
the diameter of a common pin which have just settled down, as 
well as somewhat larger and darker scales about the size of a small 
pinhead, may perhaps also be observed against the smooth bark 
on young wood. When the bark becomes quite thoroughly covered 
with the scales it assumes a rather rough, scurfy appearance of an 
ashy-gray color. When rubbed with the hand, or, better, with the 
thumb nail, a yellowish liquid appears, due to the crushing of hun- 
dreds of insects. This liquid gives a greasy feeling to the bark 
where it has been rubbed. On ver}^ young wood, especially if of 
a bright, greenish color, the scale will be surrounded by a reddish 
discoloration. This is true also on fruit, and of course it shows best 
on green fruit and on light-colored varieties. Care must be used, 
however, not to confuse the red spots formed by fungous diseases, 
such as Entomosporium maculatum, with those of the scale. 

If the outer bark, even though dark and showing no discolora- 
tion, be stripped off so as to disclose the inner green-colored portion, 
this will also be found discolored in the same way as described above, 
if the scale is present. 

The orchardist should by all means possess and learn to use a 
small magnifying glass. It will help him greatly in detecting the 
scale. Such a one as illustrated in Figure 4 can be purchased for 
about fifty cents, and for all practical purposes is as good as one 
costing ten times this amount. 

Life History. 

Unlike the larger insects with which we are more familiar, the 
scale is ovoviviparous, that is, the young are born alive instead 
of developing in eggs laid by the parent. The young larvae crawl 
about from twenty-four to thirty hours after birth until they find 
some suitable place to settle down. They then proceed to insert 
the long sucking tube into the bark, and a waxy secretion is exuded, 



24 



THE SAN JOSE SCALE. 




Fig. 5.— Underside of female scale insect, showing proboscis or sucking tube. Greatly en- 
larged. After Howard, U. S. Dept. of Agr., Bur. of Entc, Bui. 62. 



from the back of the insect, which in time gradually covers the whole 
insect and hardens into the scale. 

Soon after settling down the larva loses its legs and antennae, 
and in the case of a female the insect becomes fixed and never 
moves from its position. The larva sheds its skin several times, and 
this is added to the scale covering. In about thirty days the female 
becomes full-grown, and in a week or so thereafter begins to bring 
forth young. She continues to give birth to young at the rate of 
nine or ten a day for about six or seven weeks. 

The male scale attains maturity in about the same length of 
time as the female. 

Owing to the fact that young are being born- over such a long 
space of time from each female, it is difficirit to ascertain the num- 
ber of generations; but according to the majority of investigators, 
there are three or four in the North. Four hundred young is an 
average for each female, and the possible number of descendents 
for one over-wintering female is enormous and has been estimated 
at over three billions. 

The scale winters over in the larval stage. Insects in all stages. 



THE SAN JOSE SCALE. 



25 




Fig. 6.— Development of the scale, a— Underside of larvse showing proboscis. 6— Back of 
larva with wax exuding, c— Further development of wax secretion, rf— Larval 
scale nearly formed. 
After Howard and Marlatt, U. S. Dept. of Agr., Bur. of Ento., Bui. 62. 

of development, from the active crawling larvae to the adults which 
have completed their life history, may be found on the tree at the 
beginning of winter, but probably only those larvae which have a 
well developed scale survive. Probably not over one-eight to one- 
third survive the winters of the north. 

Description of the San Jose Scale. 



The San Jose scale, As- 
pidiotus perniciosus, Comst., 
belongs to the class termed 
''Armored Scales." In this 
class the scale covering is in 
the nature of a house for 
the insect, and does not 
form a part of its body. 




Fig. 7.— Scale of male San Jose. Greatly enlarged. 
After Atwood. 



26 THE SAN JOSE SCALE. 

The adult female scale is about ^ of an inch in diameter and 
nearly circular in outline. At or near the center of the scale is the 
highest point, or nipple, usually of a darker color than the rest, and 
this is surrounded by a concentric depressed area. Outside of this 




Fig. 8.— Cut showing characteristic form of anal plate of female, as seen under the micro- 
scope. After Howard, U. S. Dept. of Agr., Bur. of Ento., Bui 62. 

depression the scale is marked off more or less distinctly into rings 
or circular areas, some of which may have a slightly lighter j^ellow- 
ish shade than the central nipple or the margin of the scale. In 
color the scale varies from white or light yellow when 5'^oung to dark 
gray or almost black when it approaches maturity. See Figs. 1 and 6. 

The male scales are smaller, more elongated or oval in shape, and 
flattened at the extremities, with the nipple near one end. The con- 
centric rings are more plainly marked than in the female. See Fig. 7. 

The young larvse of both sexes are ovoid in shape and yellow 
in color. They have six legs, two antennae or feelers, and a long 
proboscis or sucking tube folded beneath the body. After the 
first moult, the larvse of both sexes lose their legs and antennae. 
The female becomes more or less shapeless and resembles a flattened 
sack, somewhat rounded in outline. See Fig. 5. It remains fixed 
and changes but little in succeeding moults, while the male goes 
through a number of changes, finally acquiring six legs and antennae 
again, and two wings, and backs out from under the scale as a. 
minute, active, fly-like insect. See Fig. 3. 



HOST PLANTS. 



P 



HE following list of host plants of the San Jose scale has 
been copied from a list by Dr. W. E, Britton, quoted in 
Bulletin No. 62 of the Department of Agriculture at 
Washington, In this list we mention only the trees 
and shrubs which have been observed in this State. It" will be noted 
also that the list varies a little from that of Dr. Britton's, in that 
a few plants which are mentioned as "Commonly or Badly Infested" 
have not been found so in the investigation in this State. In a like 
manner, a few that are noted in the original list as "Seldom or Never 
Infested" have been found quite badly infested in our inspection work: 

Commonly or Badly Infested. 

Amelanchier canadensis. Medic. Shad-bush, Juneberry. 
Cornus sanguinea. Linn. Red osier. Red-twigged dogwood. 
Cratoegus oxyacantha. Linn. EngUsh hawthorn. 
Crataegus coccinea. Linn. Scarlet fruited hawthorn. 
Cratcegus crus-galli. Linn. Cockspur thorn. 
Cydonia vulgaris. Pers. Common quince. 
Cydonia japonica. Pers. Japanese or flowering quince. 
Populus deltoides. Marsh. Carolina poplar. « 

Populus nigra. Linn, var italica Du Rot. Lombardy poplar. 
Prunus avium. Linn. Sweet cherry. 

Prunus cerasifera. Ehrh. var. atropurpurea. Dipp. (P. pissardi.) Purple- 
leaved plum. 
Prunus domestica. Linn. European plum. 
Prunus japonica. Thunb. Flowering almond. 
Prunus persica. Sieb. & Zucc. Peach. 
Prunus triflora. Roxbg. Japanese plum. 
Prunus virginiana. Linn. Chokecherry. 
Pyrus communis. Linn. Pear. 
Pyrus malus. Linn. Apple. 



28 THE SAN JOSE SCALE, 

Pyrus. Sp. Crab apple. 

Ribes oxyacanthoides. Linn Gooseberry. 

Ribes aureum. Pursh. Missouri or flowering currant. 

Ribes rubrum. Linn. Currant. 

Rosa. Sp. 

Rosa rugosa. Thunb. Japanese Rose. 

Salix. Sp. Willow. 

Salix -pentandra. Linn. Laurel-leaved willow. 

Salix babylonica. Linn. Weeping willow. 

Sorbus americana. Marsh. American mountain ash. 

Sorbus axicMparia. Linn. European mountain ash. 

Symphoricarpos racemosus. Michx. Snowberry. 

Syringa vulgaris. Linn. Common lilac. 

Tilia americana. Linn. American linden or basswood. 

Ulmus americana. Linn. American elm. 

Ulmus campestris. Smith. English or European elm. 

The following, mentioned in Dr. Britton's list as being "Commonly 
or Badly Infested" have not been found so in our investigation 
work, even when standing among fruit trees which have been "cov- 
ered with the scale: 

Akebia quinata. Decaisne. 

Cratcegus cordata. Soland. Washington thorn. 

Fagus sylvatica. Linn. var. purpurea Ait. European purple-leaved beech. 

Juglans sieboldiana. Maxim. Japanese walnut. 

Liguslrum vulgare. Linn. Common privet. 

Prunus serotina. Ehrh. Wild black cherry. 

Pyrus sinensis Lindl. Sand pear, including Kieffer, and Le Conte pears. 

Ribes nigrum. Linn. Black currant. 

Syringa persica. Linn. Persian lilac. 

The following, mentioned under the next heading of the above- 
mentioned list as being rarely infested, have been found quite sub- 
ject to the scale: 

Elceagnus longipes. Gray. Silver thorn. 
Rhus cotinus. Linn. Smoke bush. 

Staphylea sp. Bladder nut, which is mentioned in Dr. Britton's 



THE SAN JOSE SCALE. 29 

list as being found free from the scale, has been found badly in- 
fested in one of our nurseries. 

Occasionally or Rarely Infested. 

Acer saccharinum. Linn. Silver maple. 

Acer saccharinum. Weir'.s cut-leaved. 

Acer platanoides. Linn. Norway maple. 

Alnus. Sp. Alder. 

Cornus stolonifera. Michx. Wild red osier. 

Cornus florida. Linn. Flowering dogwood. 

Deutzia. Sp. 

Euonymus. Sp. 

Forsythia. Sp. 

Hibiscus syriacus. Linn. Shrubby althea. 

Morus alba. Sp. Mulberrj' . 

Prunus cerasus. Linn. Sour cherry. 

Rhodotypos kerrioides. Sieb. & Zucc. 

Rubus strigosus. Michx. Red raspberry. 

Sambucus. Sp. Elder. 

Viburnum opulus. Linn. Cranberry tree. 

Vitis. Sp. Grapes. 

Msculus hippocastanum Linn. Horse-chestnut, which is given here 
in the original list, has often been found among trees badly infested, 
and yet at no time have we discovered any San Jos6 scale on it. 

The following also have never been found infested, although 
it should be said in regard to them that they have not been suffi- 
ciently observed by the writer to place them definitely in the immune 
list in this State: 

Ampelopsis quinquefolia. Michx. Virginia creeper. 

Betula alba. Linn. Cut-leaved white birch. 

Buxus. Sp. Box. 

Castanea americana. Raf. Chestnut. 

Catalpa bignonioides. Walt. Common catalpa. 

Celtis occidentalis. Linn. American blackberry. 

Fraxinus americana. Linn. White ash. 

Gleditschia triacanthos. Linn. Honey locust. 



30 THE SAN JOSE SCALE. 

Juglans nigra. Linn. Black walnut. 

Kalmia latifolia. Linn. Mountain laurel. 

Ligustrum ovalifolium. Hassk. California privet. 

Lonicera. Sp. Honeysuckle. 

Picea alba. Link. White spruce. 

Robinia. Sp. Locust. 

Rubus nigrobaccus. Bailey. {R. villosus.) Common blackberry. 

Sassafras ofjidnale. Nees. Sassafras. 

Spiraea. Sp. 

Thuya occidentalis. Linn. American arbor vitae. 

Not Infested. 

Ailanthus glandulosa. Desf. Tree of Heaven. 

Andromeda. Sp. 

Aralia spinosa. Linn. Hercules' club. 

Bignonia. Sp. Trumpet vine. 

Calycanthus floridus. Linn. Carolina allspice, sweet-scented shrub. 

Carpinus. Sp. Hornbeam. 

Cedrus. Sp. Cedar. 

Cephalanthus occidentalis. Linn. Buttonbush. 

Clethra alnifolia. Linn. Sweep pepper bush. 

Corylus. Sp. Filbert,, hazelnut. 

Exochorda grandiflora. Lindl. Pearlbush. 

Gaylussacia. Sp. Huckleberry. 

Genista tinctoria. Lirm. Dyer's greenweed. 

Ginkgo biloba. Linn. Maidenhair tree. 

Gymnocladus canadensis. Lam. Kentucky coffee tree. 

Hamamelis virginiana. Linn. Witch-hazel. 

Hedera heli.c. Linn. English ivy. 

Hicoria. Sp. Hickory. 

Hydrangea (all species). 

Juglans cinerea. Linn. Butternut. 

Juniperus. Sp. Juniper. 

Laburnum vvlgare. Griseb. Golden chain. 

Larix. Sp. Larch. 

Liquidambar styraciflua. Linn. Sweet guni. 

Liriodendron tulipifera. Linn. Tulip tree. 

Magnolia {all species). 

Myrica cerifera. Linn. Wax myrtle. 



THE SAN JOSE SCALE. 31 

Nyssa syLvatica. March. Tupelo, pepperidge, black gum, sour gum. 

Qstrya virginica. Wild. Hornbeam, iron wood. 

Philadelphus coronariiis. Linn. Mock orange, syringa. 

Pinus. Sp. Pine. 

Platanus occidenialis. Linn. American plane, buttonwood. 

Quercus {all species). Oak. 

Retinispora {all species). Japan cypress. 

Rhamnus. Sp. Buckthorn. 

Rhododendron. Sp. 

Sciadopitys verticillata. Sieb. & Zucc. Umbrella pine. 

Shcpherdia. Sp. 

Smilax, Sp. 

Sophora japonica Linn. Japan pagoda tree. 

Stephanandra ftexuosa. Sieb. & Zucc. 

Tamarix. Sp. 

Tsuga canadensis. Carr. Common hemlock. 

Vaccinium. Sp. 

Wistaria. Sp. 

Xanthoceras sorbifolia.^\Bunge. 



NATURAL ENEMIES Of THE SAN JOSE SCALE. 



Dr. L. 0. Howard of the Department of Agriculture, in a recent 
bulletin by Dr. C. L. Marlatt, states that there are eight species 
of true parasitic insects which have been reared from the San Jos6 
scale. These are nearly all very minute parasites which live on their 
host insect underneath its scale. 




Fig. 9. — Mlcroweisiamisella preying on San Jos^ scale, a— Adult beetle. 6— Larya. c— Pupa 
natural size is indicated by short line near each figure, d— Calyx end of apple, 
showing beetles and larvae destroying the San Jose scale, also greatly enlarged. 
After Howard and Marlatt,U. S. Dept. of Agr., Bur. of Ento., Bui. 62. 

It will hardly be of interest to the readers of this bulletin to give 
a very full resume of Dr. Howard's account of these parasitic in- 
sects. They are not primarily San Jose scale parasites, but live also 
on other armored scales. 

The writer has in a few cases picked up scale-infested twigs which 
unquestionably showed the work of some of these little parasites, but it 



THE SAN JOSE SCALE. 33 

is needless to say that, so far, they are not even materially checking 
the pest. 

Rather more hope of relief is experienced from larger so-called 
predaceous insect enemies, chief among which are the various lady- 
bird beetles. These are well-known predaceous enemies of plant 
lice, and it is known definitely that two of the species, common in 
the State, are feeding to some extent, at least, on the San Jos6 
scale. One of these is the Twice-stabbed ladybird, Chilocorus 
hivulnerus, Muls. This is a little black, sluggish, hemispherical 
beetle with a bright red, or yellowish-red spot on each of the wing 
covers. It is about ^ of an inch in length. In no case has this 
been found in very large 'numbers. Even on badly infested trees 
the writer has seldom seen more than four or five specimens. 

The other IsLdyhird, Microweisia misella, Lee, from which we may 
expect a great deal more help, is very much smaller, only about 
^ of an inch in length, similar in shape to the former, but coal-black 
in color. In a few cases the writer has observed these little beetles 
in very large numbers on scale-infested trees. The numbers of the 
scale, however, were so great that even though numerous, the 
beetles were scarcely able to appreciably check the pest. 

On the discovery of the fact that the scale came originally from 
China, it was hoped that parasites from its native habitat might 
be introduced, and the Department of Agriculture imported a lady- 
bird, Chilocorus similis, which is said to be its principal enemy in 
that country. This is a black beetle which, in its adult form, is 
practically indentical in shape and color with the twice-stabbed lady- 
bird. It differs from our own species, however, in its larval stage, 
and also to some extent in its life' history. It has failed to become 
sufficiently acclimated to establish itself in this country, except 
in a very few places, and even in these places, it is scarcely multi- 
plying sufficiently to keep the scale in check. In time, however, 
this species may possibly establish itself more fully in some parts 
of the country, and perhaps also some of our native species will 
develop a larger appetite for the San Jose scale. It is possible, too, 



34 THE SAN JOSE SCALE. 

that many of the parasitic enemies to which we have made brief 
reference may become more active in future years. 

A few fungous and other diseases which affect the scale have been 
studied by the Department of Agriculture and some of the experi- 
ment stations, and under favorable conditions some of them may 
render valuable assistance in checking the pests in sections of the 
country favorable to their growth. 

Means of Distribution of the Scale. 

Owing to the fact that the young female moves around for a very 
brief time and can travel only a short distance, after which it settles 
down never to move again, the scale can not be distributed very 
widely or rapidly through its own efforts. Within a very restricted 
radius it is undoubtedly spread slowly through the aid of other in- 
sects. The ladybird beetles, which have been spoken of as preda- 
■ceous enemies of the scale, are no doubt occasionally responsible for 
its dissemination, as observers have frequently noted beetles of this 
kind with young scale larvae upon them. Higher animals, such 
as, birds, squirrels, etc., probably distribute a few. In orchards, 
horses in cultivating or men in pruning and harvesting may aid 
in its distribution. The wind is perhaps responsible for carrying 
it short distances, and in close plantings, interlacing branches per- 
mit distribution from tree to tree. The chief means of distribu- 
tion, however, to which we owe the very rapid spread throughout 
this country from state to state, and from one locality to another 
within the states, is through the transportation of nursery stock in 
its various forms, such as, cuttings, buds, scions, and young trees. 
It is deeply to be regretted that our country did not wake up to the 
danger of dissemination in this way when it was first discovered 
and pass the inspection laws which we now have to prevent its 
spread. 



THE SAN JOSE SCALE. 35 



Losses Due to the Scale in Rhode Island. 

Last summer an arrangement was made with the Department 
of Agriculture at Washington wherebj^ it was made possible to 
carry on a special investigation in the ravages of the scale for this 
section of the country. A large number of circular letters were 
sent out with request for information regarding the number of 
fruit trees of different kinds destroyed or injured, and also certain 
questions regarding the distribution of the scale and proposed 
methods of treating it. 

The results did not come up to our expectations. About seven 
thousand circulars were sent out and only about 550 have been 
received at the present time. It made it impossible to determine 
very accurately what the complete loss is for the whole State, but 
enough has been ascertained to give us some basis for further cal- 
culation. 

The replies gave us a great deal of information regarding the 
present situation in the State, but as this is discussed elsewhere, 
it will not be necessary to repeat it here. The blank sent out re- 
quested information regarding the number of trees of different 
kinds and ages which had been destroyed or injured by the scale. 
It also requested that the recipients in returning the blanks should 
place an estimate on the value of the trees. The latter request 
was complied with only in very few cases, and it was therefore 
necessary to secure estimates in other ways. Such estimates have 
been very kindly furnished by a number of fruit growers and hor- 
ticulturists in this and other states, and it is on these estimates 
that we base the calculations which will be given below. It may 
be said in passing that the estimates varied greatly; the value of 
a mature apple tree, for instance, being placed at all the way from 
$25 to S250. The figures which we shall use are much lower than 
the average value as calculated from the estimates that have been 
received. They are undoubtedly still too large for the average con- 



36 



THE SAN JOSE SCALE. 



ditions in this State, and the sum total of loss as derived from them 
has been still further reduced to one-third. 



Apples* 1 year $1 00 

2 and 3 years 2 00 

4 and 5 years 3 00 

6 and 7 years 4 00 

8 and 9 years 6 00 

10 and ] 1 years 8 00 

12 and 13 years , 10 00 

14 and 15 years 12 00 

16 and 17 years 15 00 

18 and 19 years 18 00 

20 and 21 years 22 00 

22 years 25 00 

26 years 30 00 

30 years 40 00 

35 years 50 00 

40 years 50 00 

45 to 60 years 50 00 

75 years 20 00 

An injured tree was valued at one-half of what an uninfested 
tree was worth. 

According to the reports received: — 

The total number of apples of all ages injured was 4,370 

The total number of apples of all ages destroyed was 1,421 

The total loss was approximately S60,300. Reducing this by 
two-thirds, gives us a total loss of $20,100, 

There are in the State approximately six thousand farms, and 
if we assume that one-half of these have apple orchards, the num- 
ber of reports is only one-sixth of the total number of farms. It 
should be reasonably fair, therefore, to multiply the $20,100 loss 
above noted by six to get the total value for the State. This w^ould 
place the loss at $120,600. This sum does not take into consideration 

♦Age given is time after permanent planting and does not include the time that the tree 
hasi grown in the nursery. 



THE SAN JOSE SCALE. 37 

the loss to the small grower in village and city. If such losses were 
counted it would probably raise the total to $160,000 or $170,000. 

To get at the proportion of loss to the total value of the orchards 
of the State, the number of bushels of apples in 1889 and 1899, as 
given by the census of 1900, were added together and divided by two 
to get the average for the two years. This amounts to 289,401 
bushels as the product of the farms of the State. Multiplying 
25 cents, which should not be too high a price as the net return per 
bushel during the last five or six years, by the above number will 
give us $72,350.25 as the net income from the apple trees of the farms 
in the State. Assuming this to be 5 per cent, interest on the value 
of the apple orchards, their total value would be $361,751.25. This 
would indicate, then, that the loss to the apple orchards of the State 
amounts to about one-third of their total value. 

The loss to pears, peaches, and plums, according to the re- 
ports received and calculated from estimates of value similar to 
those obtained for apples, amounts to: 

Pears, killed, 839 trees $8,492 70 

Pears, injured, 855 trees 6,669 75 

Peaches, killed) 6,484 trees 24,143 50 

Peaches, injured, 667 trees 1,794 00 

Plums, killed, 616 trees 1,682 25 

Plums, injured, 433 trees • 915 33 

$43,697 53 

Assuming that the estimate here, also, being for trees reason- 
ably well cared for, would be too high as an average for the State, 
and taking only one-third of the total loss, we have $14,565.84. 

Orchards of these trees are not as common, of course, as apples, 
and it would not be fair relatively to estimate that one-half of the 
farms in the State have such orchards. Assuming, however, that 
they are found on one-third, or approximately 2,000 of the farms, 
the reports which have been returned are one-fourth of the total 
number of possible reports. Multiplying the sum which we have 



38 THE SAN JOSE SCALE. 

estimated to be the loss by four, we have a total loss of $58,263.36,. 
which, when added to the loss in the apple orchards, gives a totaf 
loss of $178,863.52 for the orchards of the State. As with apples, 
many plantations of the last-named fruits are not enumerated 
as farms, and if we add the loss to that of apples outside of farms 
and this sum to the total just given, we shall have a grand total 
of over $200,000 as a conservative estimate of the loss to the apple,, 
pear, peach, and plum plantations for the last six or seven years. 
But this is not all. If loss to other trees and to shrubs which are 
attacked by the scale be added, the grand total will be still greater. 

These figures are, of course, only approximations, but it is probable 
that the loss is rather underestimated than overestimated. 

To these direct losses should also be added the loss from mis- 
directed labor in spraying, the waste of spraying materials, and 
the interest on the reduction in incomes from the farms due to the- 
destruction of the orchards. 

The Status of Fruit-Growing as Affected by the San Jose Scale. 

Fruit-tree planting, generally speaking, is at a standstill. Old- 
orchards are gradually disappearing, and the very lucrative business- 
of growing orchard crops, to which some of our lands are eminently 
suited, is fast being destroyed, except in the case of a few up-to- 
date growers who have looked the San Jose scale problem squarely 
in the face, studied the situation, secured what information they 
could from colleges, experiment stations, and agricultural publica- 
tions generally, in regard to the best methods of overcoming the 
difficulty, and have then set to work with a grim determination to 
"do or die." Such men are succeeding, and with the gradual de- 
cline of fruit-raising among their fellow growers, they are reaping 
a well-merited reward in greater demands for their fruit and higher 
prices. 

It is an oft-mentioned quotation from some horticultural lecturer,, 
that the scale is in reality a blessing in disguise, and that it is one 
of the greatest educators in fruit-growing. An uncharitable critic 



THE SAN JOSE SCALE. 39 

would immediately say that this lecturer must be one of those 
who have profited by the higher price in fruit, but there is a deal 
of truth in the statement, however, looking at it as it stands. The 
old-fashioned method of planting trees and perhaps encouraging 
them a little by cultivation or mulching until they begin to bear, 
and then expecting them to produce abundant crops of good fruit 
from year to year is at an end. In fact, if the truth had been realized, 
part of this idea was exploded long ago, even before the advent 
of the scale, for the fruit grown by careless methods was not often 
of high quality. The first-class fruit of to-day was rare. The stand- 
ard of the markets was low, and people were willing to buy and 
use second-class fruit. Cider was more generally in demand, and 
a great deal of fruit could be utilized in its manufacture. People 
were also unaware that anything better could be expected from 
their trees. To these considerations in a small measure at least — and 
to the halo that always surrounds the good old times — and not en- 
tirely to the great increase in injurious insects and fungous dis- 
eases which usually receives all the blame — is due the fact that older 
people frequently say that fruit-raising has become impossible. 

In place of the old-fashioned way has come a closer study of 
orchard work and requirements of tree growth, and partial realiza- 
tion, at least, of the principles of plant nutrition and of the fact 
that the soil is not inexhaustible in plant food, even such as is re- 
quired by orchard crops. We no longer expect to gather crops of 
fruit, and sometimes hay or pasturage, from our orchards without 
adding something to feed the plants that we grow. Cultivation 
and fertilization for orchards are taken up precisely for the same 
reason that they are used for corn, potatoes, or garden crops. 

The scale has been an educator in many other ways. The at- 
tention which the orchardist has been compelled to focus upon it 
has been reflected partly also upon other insects which have existed 
only in limited numbers, or whose depredations were looked upon 
as so much a matter of course as to escape attention. 

Plant diseases have come into notice on account of their influ- 



40 THE SAN JOSE SCALE. 

ence in checking the growth of plants or reducing the value of the 
crops harvested. Demand for information along these lines has 
grown rapidly. Agricultural colleges and experiment stations^ 
the National Department of Agriculture, and men in actual contact 
with fruit-growers and fruit-growing have been quick to study the 
crop pests, carry on experimental work, and supply much needed 
information, until we now have in America, if we are to believe 
an eminent British plant pathologist, the largest body of knowledge 
regarding spraying and related methods of dealing with injurious 
insects and plant diseases of any country in the world. 

Future Prospects. 

It is undoubtedly true that general fruit-growing in Rhode Island 
is on the decline, and many are predicting that the San Jose scale 
will reduce the total amount of fruit produced in the future. The 
latter statement is to be doubted. The hit-or-miss fi'uit-growing 
by everybody is undoubtedly approaching an end, but the large 
fruit-grower who will study the question closely and apply the knowl- 
edge gained will continue to increase his plantations. There will 
be an increase in the amount of high quality fruit and a decrease 
in that of poorer quality. The fruit growing, gravitating into the 
hands of specialists, will aid in maintaining a higher price for the 
products of the orchard, not only from the fact that there will be 
less competition, but also because there will be greater care taken 
in the growing and marketing of these products. 

The deplorable element in the present situation is the decadence 
of the home orchard. For a while, at least, the man who has a 
little land around his house will cease to plant fruit trees because it 
is too much trouble to keep them free from the scale. It is probable, 
however, that the small fruit-grower in village and city will learn 
some points in regard to spraying and care from the experience 
of the large orchardist. Dwarf trees offer a possible solution. By 
planting these he will be able to get quicker returns, keep the trees 



THE SAN JOSE SCALE. 41 

near the ground where he can readily treat them, and still get as 
large returns of good apples as in the past. In the future better 
public spraying will be carried on by men who know their business 
and do the work in a careful manner at a price which the owner 
of the trees can afford to pay. Probably, also, the San Jos6 scale 
may be approaching the height of its virulence. It is the history of 
nearly every imported insect that it increases in activity and num- 
bers for some time after it is introduced, and then, as its enemies 
develop, it suffers a gradual decline until such a time as it shall 
have reached its proper balance in the economy of nature. 

Chances of Saving Trees Badly Infested. 

Whether to try to save a tree that is badly infested is sometimes 
hard to determine, except by giving it a trial. The question is, of 
course, can such a tree be revived into a healthy tree and brought 
into a bearing condition sooner than a new tree set in its place? 

Much depends upon the age of the tree and the kind of fruit. 
Generally we may say that if a tree shows vigor, as evinced by the 
shoots of the season, it will often revive at a surprisingly rapid rate 
when pruned back and thoroughly sprayed. If the main branches 
are dying, the young shoots weak, and especially if the bark on 
the trunk begins to show lack of life and vitality, the chances for 
saving the tree are very uncertain. The question of whether to 
attempt to save a tree also depends to some extent on the grower 
himself. It is useless to try to save a badly infested tree unless he 
makes up his mind to watch the tree closely and spray thoroughly 
once a year for some time to come, and better, twice a year for the 
first year or two. 

Does It Pay to Spray. 

This question has been answered partially in the previous topics. 
Ultimately it is a question which must be answered by each man for 
himself. Where the owner of a few trees has to hire somebody to 



42 THE SAN JOSE SCALE. 

spray, pay him at a dollar per tree, and then gets perhaps 25 cents 
worth of fruit from each tree, he will naturally soon begin to think 
that spraying does not pay. When he learns how to do the work him 
self, however, in an efficient manner, it can be done for much less than 
the above figure, and no doubt most of the people who grow trees 
would be willing to keep them, even if the fruit barely pays for the 
expense of growing them. 

So far as the large grower of trees is concerned there need be 
no question. The law of supply and demand will so regulate the 
price of fruit that a reasonable return for the expense of raising 
will be received. At the present time, owing very largely to the 
presence of the scale all over the country, fruit is quite high in 
price, and there are examples in our State, as well as in others, 
that the men who spray thoroughly are reaping a good harvest. 

Aside from the destruction of the scale, other benefits which 
results from spraying, such as, cleaner and healthier trees, and the 
prevention of various plant diseases, are looked upon by many or- 
chardists as sufficient to pay for the expense of treatment. 

PRESENT MEANS OF CONTROLUNG THE SAN JOSE SCALE. 

The means of controlling the scale at the present time vary a 
little with conditions, but may be divided into: first, general orchard 
treatment; second, spraying; and third, fumigation. 

General Orchard Treatment. 

This includes, first of all, care in the purchasing of trees to see that 
the stock is not infested. As we have noted in previous discussions, 
the scale owes its distribution throughout the country almost en- 
tirely to dissemination on nursery stock. It is therefore of great 
importance: first, that no nursery stock should be purchased which 
does not bear a certificate showing that the nursery has been in- 
spected by authorized inspection officers; and secondly, if there is any 
suspicion that the scale may be present in a nursery — and such a 



THE SAN JOSE SCALE. 43 

suspicion is warranted for more than one-half the nurseries in the 
East — the grower should see to it that the stock is thoroughly fumi- 
gated with hydrocyanic-acid gas, either by the nurseryman or by 
himself. 

The old-fashioned idea of high-headed trees must also be changed. 
The trees should be headed low so that all parts can be conveniently 
and economically reached with spray remedies. The necessity 
for such a plan is not an unmitigated hardship, because it has been 
found to be more economical to have low-headed trees, not only 
for all kinds of spraying, but also for pruning and the harvesting of 
crops. When we arrive at the time to which everything now points, 
when thinning of all kinds of fruit will be more generally practiced, 
these low-headed trees will again be found most desirable. Im- 
plements are now made whereby cultivation of such trees is rendered 
easy, and the old argument for high-heading, namely, that the 
branches must be far enough above the ground so that horses can 
be driven under them, is no longer tenable. 

The low-heading necessitates, for most of the standard longer- 
lived varieties, a somewhat greater distance between the trees. 
Where 35 feet has formerly been recommended as the maximum 
distance, 40 feet is now the rule. Pruning is also much more es- 
sential than it has been in the past, not only because of the greater 
economy of time and material in spraying when surplus wood has 
been removed, but also because of the need to so shape the tree 
that it may produce a maximum of good-sized, well-shaped, and 
well-colored fruit, and a minimum of second-class fruit. Hand- 
in-hand with this goes the need of cultivation and fertilization, 
which has already been mentioned. It is coming to be realized 
that plants, physiologically and pathologically, are subject to rules 
similar to those which operate in the animal kingdom. One of 
the most important of these rules is that a plant in a thoroughly 
healthy and thrifty condition will resist injury from diseases or 
from insect parasites in a far greater degree than one which is in a 
neglected condition. It is obvious, therefore, that the cultivation 



44 THE SAN JOSE SCALE. 

and feeding of the trees so as to put them in a thoroughly healthy 
condition is of prime importance. 

Spraying. 

The discussion so far may be said to deal with preventive meas- 
ures, but in the case of the scale, even, after the greatest care has 
been exercised, it is likely that the grower will still have trouble 
on his hands, and when the pest once gets a foothold in his orchard, 
the only possible remedy is the application to the trees of proper 
insecticides. 

Brief General History of Spraying for the San Jose Scale. 

The dangerous character of the San Jos^ scale was learned very 
soon after its discovery, and experiments in methods of treatment 
were at once taken up both by the State of California and the 
United States Department of Agriculture. 

One of the first remedies tried was a lime-sulfur and salt prepa- 
ration which had been used hi California as a sheep dip. It was 
found to be quite successful and soon became a standard remedy 
in that State. When the scale was discovered in the East, the De- 
partment of Agriculture instituted experiments to try the efficiency 
of this same wash on the trees where the scale was found. For 
some reason or other, probably unfavorable climatic conditions, 
the remedy seemed to be a total failure and was abandoned for a 
time. 

Kerosene emulsion having been successfully used as a contact 
insecticide for some time, attention was next turned to this and 
other oil preparations with a view of securing some efficient spray 
remedy. The kerosene emulsion, made according to the standard 
formula, was soon found inefficient, impracticable and too expensive, 
and extensive trials were made with kerosene and water and crude 
oil and water mechanically mixed by means of pumps especially 
prepared for the purpose. The general purpose of the experimen- 



THE SAN JOSE SCALE. 45 

tation was to determine the insecticidal value of the oil solutions, 
and also their effect upon the trees. It was at first supposed that 
an efficient remedy had been discovered in crude oil, which, when 
applied in sufficient strength, would generally destroy the scale. It 
was found, however, that the results were in many cases unsatis- 
factory because, of the injury to and sometimes total destruction 
of the trees to which the remedy was applied. 

Attention wa& again turned to the lime-sulfur wash, not only by 
the Department of Agriculture, but also by various experiment 
stations throughout the infested regions, and this time with a great 
deal better results. 

Later a new kerosene oil remedy, prepared by mixing a hydrated 
lime called "Limoid" and kerosene, ready-made lime-sulfur washes, 
and a number of so-called "soluble," or more correctly, miscible, oil 
preparations have been recommended, all of which are considered 
more or less successful by various experiment stations and growers. 

A few years ago a certain agricultural newspaper took up the 
discussion and announced that caustic potash was a sovereign remedy 
for the scale. When applied at a certain strength it was undoubt- 
edly efficient in destroying the insect, and the success at first was 
such that it promised to become a universal remedy. Although 
it was not generally recommended by agricultural experiment 
stations, its success was such that many who used it were inclined 
to criticise the station workers for their slowness in discovering 
its virtues. This conservative attitude on the part of the experi- 
ment stations has, however, been amply justified in recent develop- 
ments, for we no longer hear caustic potash recommended as a 
remedy against the scale. 

History is repeating itself at the present time in that experiment 
stations are being criticised for not unqualifiedly recommending 
the use of the miscible oils. The champions of these remedies argue 
that the oils are much easier to prepare and apply, are fully as effect- 
ive as the old-fashioned lime-sulfur wash, and but little more ex- 
pensive. Two or three stations in their experiments have gotten 



46 THE SAN JOSE SCALE. 

very satisfactory results from the use of these oils and are recom- 
mendirig them freely. In other cases, however, the stations have 
not had such good results, and as the oils have not been used 
long enough by all kinds of growers on different kinds of trees to 
fully establish the effect of more or less continuous use, general 
recommendation has been withheld. 

The Lime-Sulfur Wash. 

The weight of opinion at the present time seems to be in favor 
of the home-made, boiled lime-sulfur wash, and since it is of con- 
siderable importance to understand the methods of preparation 
of this remedy, a somewhat extended discussion of it will be given. 

Since the lime-sulfur wash was first used, a great many formulas 
for its preparation have been tried and recommended. In its early 
history in California it was made from lime, sulfur, and salt, and 
when the first experiments were conducted in the East the California 
formula was followed, the only variation being in the proportion 
of the ingredients. In Oregon an attempt was made to combine 
in the lime-sulfur wash greater efficiency as a fungicide, and a quan- 
tity of copper sulfate was added. In the East the disagreeable 
work of preparing the wash by boiling led to an attempt to find 
some means by which it could be prepared without this labor, and 
the addition of caustic potash and carbonate of soda was recom- 
mended. Recent experiments have indicated that the addition 
of salt is unnecessary, and that the attempt to increase its fungi- 
cidal properties by the addition of copper sulfate is detrimental. 
Preparations with caustic potash and soda have been found less 
efficient and more expensive than the boiled wash. 

The following formulas will give an idea of the different ways 
in which the remedy has been prepared: 



THE SAN JOSE SCALE. 



47 





1 

e 

3 


CO 


1 


3 


1 

as 

-0 

o 

02 

.2 

3 

6 


a 
a 
o 

o 


"3 

<u 

1 


.a 

B 

|1 


Original California Sheep 
Dip 


80 
30 
15 
50 

50 
15 
40 
30 
20 
15 
15-20 

20 

13^ 

pure. 


100 
15 
15 
50 

50 
15 
20 
15 
14 
15 
15 

15 
25 


10 
10 


20 






160 

60 

45 or 60 

150 

150 
50 
60 
50 
40 
50 
50 

50 
100 




Present California Wash . . 






1-2 hrs. 


Piper's Formulas 

Regular Oregon Wash, 1907 

Special Lime-sulphur Wash 
with copper sulphate 
(known in East as Ore- 
gon Wash.) 

Illinois 








1 hr. 










Ihr.-h 

1 hr.-f 
Uhr. 








8-10 


15 
15 






New York (Geneva) 

Linie-Sulfur-Caustic Soda . 








2-2^ hrs. 




5 






Conn. Exp. Station Wash . 
R. I. Bulletin 100, 1904 . . . 


10 
5-10 












40-50 min. 


R. I. Circulars, 1905 








1 hr 


U. S. Dept. of Agriculture, 
1906 










1 hr. 


Chemical 

























Reducing these formulas to a uniform quantity of water, say 
100 gallons of complete spray solution, will indicate more easily 
the wide varaition in amount of lime and sulfur. 



48 



THE SAN JOSE SCALE. 





4/" 

a 

3 


3 

m 


1 
"a 


1 

tic 

3 

CO 


si' 

■o 
eg 
o 
-.3 

3 

6 


1 

3 

u 
<o 

a. 

a. 

6 


4 

1 


s 


Original California Sheep 
dip 


50 

50 

25 

33i 

33J 
30 

60 

50 

30 

30-40 

40 

13* 

pure. 


62+ 
25 
25 

33§ 

33^ 
30 

33J 
30 
35 
30 
30 

30 
25 


6i 
16f 


12^ 






100 
100 
100 
100 

100 
100 
100 
100 
100 
100 
100 

100 
100 




Present California Wash. . 








Piper's Formula 








(60) 


Regular Oregon Wash, 1907 

Special Lime-sulphur with 

copper sulphate (Icnown 

in East as Oregon Wash.) 

Illinois Wash 
















5Mf 




30 
25 








New York (Geneva) 










Lime-Sulfur-Caustic Soda. 




10 






Connecticut Exp. Station. 
R. I. Bulletin, 1904 


25 
10-20 














R. I. Circular, 1905 










U. S. Dept. of Agriculture, 
1900 












Chemical 

























Careful experimental work coupled with chemical analyses dur- 
ing the past two or three years is gradually doing away with the 
diversity of formulas, and one of the simpler ones will undoubtedly 
be generally recommended all over the United States. 



Formula for the Lime-Sulfur Wash as Generally Recommended at 

the Present Time. 



In the light of the present knowledge regarding the lime-sulfur 
wash, then, we can fully recommend the mixture made according 
to the formula and directions which have been sent out in Bulletin 
No. 100 of the Rhode Island Experiment Station, with the excep- 
tion that the salt may be left out if the operator so chooses. 



THE SAN JOSE SCALE. 49 

The formula is as follows: 

Stone lime, freshly burned, and of good quality 15 or 20 lbs. 

Sulfur, flowers of, finely ground 15 lbs. 

(Salt, if used) 10 lbs. 

Water 50 gals. 

The mixture may be boiled either in barrels with steam or in 
large iron kettles with direct application of fire. In either case 
the preparation should be as follows: 

Slake the lime with a small quantity of boiling water, only suffi- 
cient to keep the lime well covered being used. Mix the sulfur 
with water into a thin paste and add it to the lime as soon as the 
slaking begins. In this way the heat generated by the lime is used 
to combine partly the lime and sulfur. Stir the mixture thoroughly, 
and after the slaking ceases add hot water to make 20 or 25 gallons, 
according to the size of the kettle or barrel. If salt is used it 
should be added at this time. Boil in kettles or in barrels by 
means of steam. If kettles are used, continue the stirring, and in 
any case boil from 45 to 60 minutes. Strain into spray barrel through 
a wire sieve with not less thah twenty meshes to the inch. Make up 
to 50 gallons, and apply at once. 

The color of the prepared mixture shoidd be a dark orange-yellow 
when well stirred. If allowed to settle, the liquid at the surface 
should assume a dark oxblood color. 

If the lime used is of good quality, so that but little sediment re- 
mains in the bottom of the kettle, 15 pounds are sufficient. Should 
there be any question as to its purity, however, it is best to use 20 
pounds. 

INGREDIENTS OF THE LIME-SULFUR WASH. 

The Lime. — The lime is fresh or unslaked plasterer's lime, 
produced by means of heating or "burning" limestone. Pure 
limestone, of which white marble is the most common example, is 
calcium carbonate CaCOg. When this is strongly heated, carbon 
dioxide (COg) is driven off, and pure lime, calcium oxide (CaO) remains. 

7 



50 THE SAN JOSE SCALE. 

The ordinary limestone from which our lime is made is seldom 
pure, so that the quicklime or CaO, bought on the market is 
usually impure. The chief impurities are sand and larger fragments 
of igneous rock and magnesia (MgO) derived from magnesium 
carbonate in the limestone. 

The lime for the making of the lime-sulfur wash should be rea- 
sonably pure, and free from the above-mentioned impurities. If 
after a thorough boiling for an hour a great deal of sediment remains 
in the bottom of the kettle or other vessel in which the boiling took 
place, it indicates that the lime is impure, and more must be used. 
Good lime should not contain over 10 per cent, of impurities. 

Sulfur. — This substance is found free in nature especially in vol- 
canic regions, but also, in combination with various minerals, chiefly 
iron. It is mined in its free state or reduced from its ores. The 
former is called crystalline sulfur, and the latter is the common 
Tarimstone. Brimstone is heated in retorts which vaporize the 
sulfur and conduct the vapors into especially constructed conden- 
sation chambers. While the walls of the chamber are cool the sulfur 
vapor condenses on them in very fine- particles, which are scraped 
off and called flowers of sulfur. Later the chamber becomes so 
hot as to condense the sulfur merely to a molten mass which is run 
out into moulds and becomes the stick sulfur of commerce. From 
this are made the various grades of ground and finely ground sulfur. 

The flowers of sulfur were formerly recommended as being pref- 
erable for the preparation of the lime-sulfur wash, but lately the 
finely ground sulfur has come into use. It readily enters into 
combination with the lime, and is equally good so far as efficiency 
is concerned. It should be used exclusively, since it is usually 
somewhat cheaper. The crystalline sulfur has been tried, but it 
enters into combination more slowly and requires much longer 
boiling. 

The salt, if used., is common commercial chloride of lime; and 
the caustic soda is the ordinary brand, which can be purchased quite 
cheaply in the market. 



THE SAN JOSE SCALE. 



51 



APPARATUS FOR PREPARING THE LIME-SULFUR "WASH. 




Fig. 10.— Strainer for straining spray 
solutions into tanls.— Goulds' Mfg. Co. 



Convenient apparatus for the boiling 
of the lime-sulfur wash is essential for 
its economic preparation. If to be 
prepared in small quantities, two sugar 
kettles of 25 to 30 gallons capacity, 
one for heating water and the other 
for boiling the wash, with the addition 
of a barrel for holding the supply of 
water, will serve the purpose very well. 
The details of such an arrangement 

can be easily learned from referring to Fig. 21. With this arrange- 
ment one man can readily prepare a fifty-gallon lot of the wash while 
three men with hand pumps are putting it on the trees. Where more 
than one hand pump or a power sprayer is operated, a steam boiling 
outfit is almost a necessity. Such outfits are illustrated in Fig. 20 and 
Plate XVI, Figs. 1 and 2. The essentials of the arrangement are a 
steam boiler and a numljer of ordinary kerosene barrels in the 
bottom of which are fixed perforated gas pipe connected with the 
main steam pipe for the escape of the steam. One of the barrels 
is used for heating water and the others for boiling the wash. The 
forcing of steam into the bottom of the barrels creates sufficient 
disturbance in the liquid so that stirring is not necessary. A main 
water supply from tank or hydrant conveniently located is a neces- 
sary adjunct to such an arrangement. 

The platform on which the barrels stand should be high enough 
so that the prepared solution can be led through the outlet pipe 
into the spray tank or barrel by gravity. Valves should be provided 
for both the steam and outlet pipes of each barrel. The valve of the 
outlet pipes should be so constructed as not to be readily clogged. 
The boiler should be of 1 horse-power capacity for each barrel used. 

Both of these arrangements can be used out ©f doors. If the 
boiling is done in a building, it is better to use one that is not 



52 THE SAN JOSE SCALE. 

pjiinted, as the fumes from the sulfur escaping through the doors 
and windows are likely to discolor the paint around these openings. 

CHEMICAL COMPOSITION OF THE LIME SULFUR WASH. 

It is beyond the purpose of this bulletin to discuss at length the 
chemistry of the lime-sulfur wash, but inasmuch as the work which 
has been done by the United States Department of Agriculture, 
and by a number of stations, notably Massachusetts and Washing- 
ton, is throwing a great deal of light upon the question of what 
should be the best formula, a few notes from the bulletins of the 
above named stations will be given: 

According to Professor R. W. Thatcher of the Washington Agri- 
cultural Experiment Station, properly prepared lime-sulfur washes 
contain a total sulfur in chemical combination nearly equal to the 
amount of sulfur used. This sulfur exists in a variety of compounds, 
but chiefly in what are called sulfid sulfurs. These sulfid sulfurs, 
according to Bulletin No. 116, by Dr. Fernald of the Massachusetts 
Agricultural College, are of different composition, namely: Mono- 
sulfid CaS; Calcium Hydrosulfid CaCSHg); Calcium Polysulfids 
CaSs, CaS4, CaS-. In addition the wash contains the following 
sulfur and calcium compounds: Calcium Thiosulfite CaS203; 
Calcium Sulfite CaSOg; Calcium Sulfate CaS04, Gypsum; Calcium 
Hydrate Ca(OH); and Calcium Carbonate CaCOg, Limestone. 

In connection with such chemical studies, experimenters have 
been led to believe that the sulfid sulfur compounds are the im- 
mediately active insecticidal agents in the wash. The thiosulfate 
is more slowly decomposed, and is responsible for the somewhat 
prolonged efficiency of the mixture. It is not yet known in what 
way the sulfur compounds act upon the scale, but it is thought 
that in the rapid decomposition of these sulfids in contact with the 
air, minute particles of free sulfur are liberated, and that these, 
either in themselves or by combination with the oxygen of the 
atmosphere, as sulfuric dioxide — quite well-known to us in the 
old-fashioned sulfur matches — in some way destroy the insect. 



THE SAN JOSE SCALE. 53 

These chemical analyses have also given the following interesting 
facts regardhig the composition and action of the lime-sulfur washes: 
The addition of copper sulfate reduces the amount of the sulfid sul- 
fur compounds by forming an insoluble copper sulfid which is prob- 
ably of little use, either as an insectcide or fungicide. The salt does 
not enter into any chemical combination with the lime and sul- 
fur, and the wash is in no way influenced by the presence or ab- 
sence of this substance. This emphasizes the conclusion, which 
has been reached in a more general way by experiments in the 
application of the wash, that the addition of salt is largely a useless 
expense. 

Thatcher mentions, as a further conclusion from his analyses, 
that the greatest quantity of effective sulfur compounds is obtained 
most cheaply in some of the simpler formulas, preferably those 
of Professor Piper, formerly of the Washington School of Science. 
These are designated as Piper's 1 :1 :4 and 1 :1 :3 formulas. The formu- 
las mean of course that 1 pound of sulfur and 1 pound of lime are 
used with either 3 or 4 gallons of water. Reduced to the more com- 
mon way of stating them, these formulas are practically the same 
as the one recommended by the Illinois and various stations of the 
East, with the exception of the salt, and followed up to the present 
time by the Rhode Island College and Station: namely, 15 pounds 
•of sulfur, 15 pounds of lime, and 50 gallons of water. In the case of 
Piper's formulas, it would be either 45 gallons of water or 60 gallons 
of water. 

The chemical work has also shown that certain proprietary reme- 
dies, such as the "Rex" Lime and Sulfur compound, when fresh 
at least, are quite equal to the home-made mixtures in the amount 
of sulfid and thiosulfate compounds. With the dilution of the 
stock solution that is recommended by the manufacturers of the 
"Rex" wash, however, the amount per gallon is not as great as 
that in the home-made mixture, according to the 1:1:3 formula, 
a,nd, consequently, it should be used somewhat stronger than recom- 
mended. 



54 THE SAN JOSE SCALE. 

An interesting fact shown by the analysis conducted at the Massa- 
chusetts Experiment Station is that calcium carbonate, calcium 
sulfite, calcium sulfate, more or less inactive as insecticidal agents,, 
and thiosulfate, are rapidly increased in quantity after the solution 
has been prepared, and the sulfid compounds are decreased. This 
seems to corroborate the general opinion that the freshly prepared 
wash is more effective and desirable to use than one which has been 
standing for some time. Quaintance, in a bulletin of the Department 
of Agriculture, states that the reheated wash does not differ in com- 
position from the freshly made. Some of the sulfur is crystallized 
on boiling, but this will dissolve again on reheating. The writer 
has been unable to find any analyses of reheated washes, but other 
analyses show that continued boiling as well as standing after pre- 
paration increases the less-active sulfur compounds in the wash, 
and it would seem as if this would prove that reheated washes 
are not as good as the fresh. Practical experience, as already 
alluded to, so far as it throws any light on the subject, seems ta 
substantiate this conclusion. 

Chemical analyses have shown that the formulas which depend 
upon the combination of the sulfur and lime through the heat of 
the slaking lime only are faulty because only about 8 per cent, 
of the sulfur is brought into solution. Such analyses have also 
shown that at the end of 45 minutes of thorough boiling practically 
all of the sulfur has entered into chemical combination, and that 
nothing is gained by continuing the boiling for more than one hour. 
In fact, indications are that certain of the more active polysulfids 
change into less active thiosulfate or calcium sulfate. 

The amount of lime recommended in the standard formula is 
nearly twice as great as that required to combine with the sulfur. 
The surplus lime remains as a whitewash and gives the light-yellow 
color to the well-stirred wash. It is useful in giving color to the 
wash so as to show what trees have been treated and how thorough- 
ly the work has been done. It may possibly also aid in holding the 
wash on the trees until the less-active thiosulfate compound has 



THE SAN JOSE SCALE. 55 

iDecome active. The "Chemical" formula already given in the 
table on page 47 is made to supply just sufficient lime for combina- 
tion with the sulfur. 

OTHER LIME-SULFUR REMEDIES. 

The Lime-Sulfur Caustic Soda Formula. 

Fresh stone lime of good quality 30 lbs. 

Sulfur, finely ground or flowers 15 lbs. 

Caustic soda 5 lbs. 

Water 50 gals. 

This wash is prepared in the same way as the boiled wash, with 
the exception that after the sulfur has been added 5 pounds of caus- 
tic potash is gradually put into the mixture and no boiling is done. 
Stir the mixture thoroughly, adding fresh hot water to make a 
thin paste. After the soda is dissolved, make up to the required 
amount of the formula and strain as in the previous mixture. When 
well prepared this is a fairly efficient mixture and probably equal 
to anything, excepting the miscible oils and the boiled lime-sulfur 
wash. 

Hayward, in Bulletin No. 101, Bureau of Chemistry, Depart- 
ment of Agriculture, recommends that this wash should be prepared 
as follows : 

Make the sulfur into a thin paste with hot water, and add the 
caustic soda. Stir the mixture thoroughly for fifteen minutes and 
add the lime. Allow the lime to slake and add more hot water, if 
necessary, in order to keep the lime well covered. After the slaking 
ceases, add fresh water to make 50 gallons. 

The Self -Boiled Lime-Sulfur Wash. 

The two formulas already given are now considered as the best, 
but the following notes on another method may be of interest. 



56 THE SAN JOSE SCALE. 

Lime 30 lbs 

Sulfur 15 lbs. 

Water 50 gals. 

The preparation is the same as that for the boiled sulfur, except- 
ing that the slaking lime is relied upon to dissolve the sulfur instead 
of boiling. As has already been noted under the chemistry of the 
lime-sulfur wash, this wash is not satisfactory. 

Several proprietary remedies are sold on the market, among . 
which are Calcothian and Horicum. There is not as yet sufficient 
evidence in regard to the effect of these on which to base definite 
conclusions. 

Thatcher, in his bulletin on the lime-sulfur washes, mentions 
another proprietary remedy, the Rex lime-sulfur wash, which he 
considers to be very good, providing it is fairly fresh and used some- 
what stronger than the manufacturers recommend. 

Remedies Derived from Petroleum. 

Kerosene in the standard emulsion, the formula of which need 
not be repeated h^re, was early used in an attempt to control th& 
scale. It was found, however, that its chief value lay in its use as 
a summer spray to check the too rapid development of the scale. 
Nevertheless it was recognized that petroleum oils possessed 
considerable merit as contact insecticides, and efforts were made 
to secure a formula or method by which they could be utilized 
in some form. Pumps have been designed which will spray a me- 
chanical mixture of kerosene or crude oil and water, and at one 
time this method was generally recommended. The New York. 
Experiment Station has been active in the testing of various prep- 
arations containing petroleum, and the following notes in regard to 
the use of kerosene and crude oil have been gathered largely from 
the bulletins of this station. 

Under favorable conditions, common kerosene of the best grades, 
150° flash test, or better, and water, mechanically mixed of the: 



THE SAN JOSE SCALE. 57 

strength of from 15 to 25 per cent., can be used on apples and pears 
in the summer time with little or no injury. On stone fruits, a mix- 
ture of this strength is frequently detrimental. Kerosene of this 
strength, however, is of no value against fully-formed San Jos6 
scale, and can only be used, like kerosene emulsion, as a check for 
the recently settled young scale and the crawling larvae. 

A 40 per cent, solution of good grade kerosene can be applied to 
dormant pear and apple, and this mixture is fairly efficient in de- 
stroying the scale. Under favorable conditions, and when the 
trees are entirely dormant, pure kerosene has been used on pears 
and apples without any appreciable detrimental effect; but even 
the 40 per cent, solution above mentioned is injurious to these 
trees if applied after the sap starts in the spring. On the other hand, 
peculiarly enough, stone fruits react in an entirely different way. 
A mixture containing 25 per cent, of kerosene is injurious to trees 
of this kind during the dormant season, but much higher amounts can 
be used after the buds begin to swell and before the leaves come out. 

All so called reduced oils or gas oils of specific gravity .837, or 
35° Baume, are unsafe at any time on any tree, while the lighter 
grade of specific gravity .79, 44° Baum^, or not less than 40° Baum6 
at 60° temperature, can be used at any time in the same way as 
kerosene. 

The great difficulty in using these mechanical mixtures of oil 
and water is that no accurate pump has as yet been devised. Most 
of them will vary the amount of oil sprayed 5 per cent, or more on 
either side of the percentage fixed. Efforts have, therefore, been 
made to find some way of producing an emulsion of water and oil, 
and the following remedies have been recommended. 

KEROSENE LIMOID MIXTURE. 

A few years ago Professor C. P. Close recommended hydrated 
lime as an emulsifier. The Charles Warner Co., of Wilmington, 
Delaware, put out the required form of lime under the name of 
Limoid. The formula was as follows: 

8 



58 THE SAN JOSE SCALE. 

Kerosene 1 gal. 

Limoid 4 lbs. 

Water sufficient to make the solution of the required per- 
centage of oil. 

It was claimed for this kerosene-limoid mixture that it is easily 
made and applied; that it colors the trees the same as the lime- 
sulfur wash, so that it is easy to see whether they have been well 
covered; that, like all oil preparations, it spreads more thoroughly 
over the whole surface of the bark than the lime-sulfur washes; 
and that it is equal in efficiency to these washes. 

Experience has not wholly borne out the claims based on the 
early experiments, and in recent years certain other oil prepara- 
tions have been recommended under the name of 

MISCIBLE OILS. 

Formulas for the home preparation of these have been published 
by the Delaware Experiment Station and by the Storrs Experiment 
Station of Connecticut. The following notes are taken from a re- 
cent bulletin of the latter station: (There are three parts to the 
process of preparing the oil according to the formulas given. Note 
also that the author uses the term "soluble oil" instead of miscible 
oil.) 

Emulsifier. 

Carbolic acid (crude liquid 100 per cent.) 2 qts. 

Fish oil 2i qts. 

Caustic potash (granulated) 1 lb. 

Heat to 300° F., remove from fire, and immediately add: 

Kerosene 3^ qts. 

Water 5^ qts. 

"This formula is sufficient to make 13 gallons of the complete 
soluble oil or 208 gallons of the spray mixture. It may be made up 
in any quantity and kept indefinitely. It is the most complicated 
part of the formula, but little difficulty will be experienced if the 



THE SAN JOSE SCALE. 59 

proper materials are used. The cooking is best done in an iron 
kettle. An ordinary kettle or caldron, commonly used on the farm 
for making soft soap, will answer the purpose. It should be equipped 
with a cover and so arranged that it can be readily removed from 
the fire, and should not be more than half filled to allow for foaming. 
The mixture being infiammable when hot, the cooking should not 
be done inside or near a building, unless, of course, a steam coil 
or jacketed kettle is used, and care should be observed in prevent- 
ing the fire from blazing up around the top of the kettle. A good 
thermometer graduated to about 320° F. will be necessary. If the 
local dealers are unable to supply thermometers of this description, 
they may be purchased at one dollar each from Eimer & Amend, 
205-211 Third Ave., New York. Five cents extra should be en- 
closed to cover postage." 

" The various rnaterials should be added separafeli/ in the order 
named and while the whole is being stirred. When the operation has 
been completed, the resultant mixture will thicken up and present, 
except for its darker color, somewhat the appearance of soft soap." 

The Complete Soluble Oil. 

Emulsifier 8 parts. 

Crude petroleum 18 parts. 

Rosin oil 4 parts. 

Water 1 part. 

"Although the soluble oil will remain in good condition for a long 
time, it seems advisable to prepare this, the second part of the 
formula, just before using." 

"By securing the materials in large quantities, the soluble oil 
may be made for 16 to IS cents per gallon. If diluted with fifteen 
parts of water, as is recommended, the spray mixture costs slightly 
over one cent per gallon. In view of its spreading action when 
applied to the tree, and from the fact that it can be sprayed with a 
fine nozzle, one gallon will go much farther than the same quantity 
of lime and sulfur." 

To use this "soluble oil" stir thoroughly, and to one part of the 
oil take fifteen parts of water. When about to mix large quantities, 
it is well to test the miscibility of the oil by pouring a few di-ops 



60 THE SAN JOSE SCALE. 

in a glass and stirring it. If a good milky emulsion without free 
oil on the surface is formed, the stock solution is all right to use. 
It is further added, in regard to this method, that absolutely clean 
spraying utensils should be used. Bordeaux mixture, Paris green, 
or lime-sulfur are liable to spoil the emulsion. 

PROPRIETARY REMEDIES FROM PETROLEUM. 

Various proprietary remedies made from petroleum oils under 
the name of "soluble" or "miscible oils" are sold on the market. 
Among these are Scalecide, Kil-0-Scale, Target-brand Scale De- 
stroyer, etc. 

These are quite well-known, and are generally well recommended 
by users. Scalecide has come into prominence in this State perhaps 
a little more than the others, and indications are that for those 
who cannot prepare their own spray solutions, or who have only a 
small amount of spraying, it can be recommended as a safe and 
efficient remedy. 

Comparative Value of the Lime-Sulfur Wash and Miscible Oils. 

There is quite a little discussion as to the comparative value 
of the lime-sulfur wash and the miscible oils. It is claimed for the 
lime-sulfur wash that it is cheap; effective; not injurious to the 
trees; that it has a prolonged action; gives evidence by color of the 
thoroughness of spraying, which is a very important part, especially 
when the spraying is done by some one not the owner of the trees; 
if applied in the spring of the year it forms a partial protective 
coating over the bark which prevents the settling down of young 
insects that may be born early in the season; that it has been found 
efifective against the pear tree psylla, and probably also destroys 
a great many eggs of plant lice; and that it is effective as a 
fungicide, especially against leaf curl of peaches and probably 
also against brown-rot of the same fruit, and possibly apple 
scab. 



THE SAN JOSE SCALE. 61 

Its disadvantages are that it is laborious and difficult to make and 
disagreeable to apply; it must be thoroughly sprayed, for it does 
not spread like the oil preparations, and for this reason it is probably 
not so effective as the oil sprays on trees with rough bark, such as 
old apple and pear trees; the solution is quite corrosive and injuri- 
ous to spraying apparatus, and caustic to horses and to men doing 
the spraying. 

It is claimed for the oils that they are easy to mix and apply; 
that they spread well, and absolute thoroughness in covering is not 
so essential as with the lime-sulfur wash; that they are not hard on 
machinery, except perhaps the hose; and that they are quite effective, 
and are advantageous, especially for the small grower. 

The disadvantages are that they are rather high in price, if pro- 
prietary remedies are purchased, and laborious to make, if to be 
be prepared at home; that they are practically colorless and do 
not indicate whether spraying has been thorough; that the effect 
is practically immediate, and there is no protection to the bark 
against future infestation; and that they have but little, if any, fun- 
gicidal value. 

Miscellaneous Spray Solutions for the San Jose Scale. 

Whale Oil Soap. 

Whale oil soap 2 lbs. 

Water 1 gal. 

It is essential to secure a good potash soap and the following brands 
are recommended by the Massachusetts Experiment Station: 

Good's caustic potash and whale oil soap. 
Good's caustic potash and whale oil soap No. 3. 
Bowker's Tree Soap. 
Leggitt Brothers Anchor Brand. 

The whale oil soap spray has been found by the United States Depart- 
ment of Agriculture to be about as efficient as the lime-sulfur wash. 



62 THE SAN JOSE SCALE. 

It is somewhat disagreeable to handle, and when cold it is difficult 
to apply. The chief objection to it, however, is that it costs about 
eight times as much as the home-made lime-sulfur wash. 

Resin Wash. 

A mixture composed of the following ingredients has been used 
against certain kinds of soft scales in California, and is claimed by 
some to be of value against the San Jose scale : 

Resin 20 lbs. 

Concentrated lye 4 lbs. 

Fish oil 2^ pints. 

Water 100 gals. 

Place the resin, lye, and oil in a kettle with sufficient water to 
cover to a depth of three or four inches. Boil about two hours, 
adding more water if necessary. Dilute with hot water up to one- 
third of the final quantity, and finally make up to 100 gallons. This 
is a stock solution. 

A New Wash Proposed by the Department of Agriculture at 
Washington. 

J. K. Hay ward who has made quite an exhaustive chemical 
study of the lime-sulfur washes in the various combinations, pro- 
poses the following formula, which he claims is much more easily made 
than the solutions already mentioned and has the required amount of 
sulfur compounds as polysulfids and thiosulfates. While theoretically 
it is probably not as desirable for this climate as the lime-sulfur 
wash, on account of the fact that it is more easily washed off the 
trees by rains, nevertheless it may, on account of its simplicity, 
be worth a trial. 

The proposed formula is as follows: 

Powdered sulfur 19 lbs. 

Caustic soda 10 lbs. 

Water 50 gals. 



THE SAN JOSE SCALE, 63 

A paste is made of the sulfur with about five and one-half gallons 
of boiling water. The caustic soda, which should be in small pieces, 
is then added, and the mixture is stirred occasionally for about half 
an hour; then 44^ gallons of water are added; the mixture is again 
stirred, and should then be ready for use. Should it be desired 
to add lime as a marker, and possibly as a means also of holding 
the wash on the tree. Hay ward recommends that about 17 J pounds 
of slaked lime be added. The lime is slaked with enough water to 
make a thick paste, and added to the sulfur and caustic soda just 
before making up to 50 gallons. 

A proprietary wash, sold under the name of "Con-sol," has been 
found by Thatcher of Washington to be a sulfur-soda wash, and 
probably is made in some such manner as the above mentioned. 

Comparative Cost of Spray Solutions. 

It is impossible to give exact cost, because the prices fluctuate 
from year to year, and also vary with the different places where 
they are sold. The following prices of ingredients and proprietary 
remedies are approximately correct for the present year. From 
these any one can figure out the cost of the various spray remedies. 

Lime $8.00 per ton, or about $1.00 per barrel of 250 lbs. 

Sulfur $2.50 to $2.60 per hundred pounds in barrel lots, F. 0. B. New- 
York. 

Salt about 35 cents per hundred pounds. 

Caustic soda $4.50 per cwt. in 10 lb. cans. 

Whale oil soap. . . .4 cents to 5 cents per lb., by the barrel. 

Kerosene 11 cents to 13 cents a gal. by the barrel. 

Crude oil about 12 cents a gallon. 

Limoid $2.50 and $5.00 per hundred pounds. 

Scalecide $1.00 a gal., or 50 cents a gal. in barrel lots. 

Horicum $1.00 a gal,, or 50 cents a gal. in barrel lots. 

Kil-0-Scale $1.00 and $1.50, according to quantity. 

Calcothian 5 cents per gal. by the barrel. 



64 THE SAN JOSE SCALE. 

The Time of the Tear to Spray. 

There has been much discussion regarding what time of the year 
the spraying should be done. It seems to be quite conclusively 
proven that fall or spring spraying is much more effective than win- 
ter spraying, probably because of greater resistive powers of the 
scale during the winter when entirely dormant. 

A late spring application, especially with the slow-acting lime- 
sulfur wash, will probably not only have an immediate effect upon the 
scales which are reviving after the winter's rest, but will also con- 
tinue to work on the scale, through the less quick-acting thiosulfate 
compounds, for some time after the leaves have come out. 

In the fall of the year, immediately after most of the leaves have 
fallen, the scale is undoubtedly still in an active condition in this 
climate. Many young can still be seen crawling about, and the 
apphcation of a spray is undoubtedly very effective. It may be 
reasoned that at this time of the year an oil spray would be fully as 
effective as a lime-sulfur wash, provided that it is applied in such a 
form and quantity as not to be injurious to the partially dormant 
trees. 

There seems to be little choice, therefore, between fall and spring, 
except such as depends upon the kind of spray used. If the trees 
are badly infested they should be sprayed both in the fall and in 
the spring. The old idea which was published rather freely a few 
years ago, that a single spraying once in two or three years was 
sufficient to keep the insect in check, has been entirely exploded. 
The orchardist will have to make persistent annual attacks if he 
wishes to keep his trees clean, and when the trees are thoroughly 
covered, two applications a year are none too much. 

Methods of Applying Spray Remedies. 

As much depends upon the careful application as on the remedy 
itself. Squirting a few gallons of some patent mixture at a tree 
when time permits is usually time and money wasted. As noted 



THE SAN JOSE SCALE. 65 

under the discussion of the scale, it multiplies so rapidly that a 
very few which survive the winter and the application of the spray 
compounds will in the course of a summer increase to such an ex- 
tent that the grower, on examining his trees in the late autumn, 
will probably wonder whether his spraying was of any use whatever. 
It is therefore absolutely essential, no matter what spray mixture 
is used, to cover the trees thoroughly. Paint brushes, whisk brooms, 
carriage-washing outfits, garden hose, and other ancient and ven- 
erable spraying outfits must be delegated to the domain of the old- 
fashioned gardeners. The up-to-date orchardist must secure for 
himself a spray outfit which will do the work according to modern 
principles. This does not necessarily mean that he will have to 
purchase expensive apparatus. There are good outfits designed 
for all kinds of spray work and for spraying a few trees as well as 
for spraying large orchards. 

The second requisite for effective work is careful manipulatioii 
of the nozzle in applying the mixture. A good worker will thor- 
oughly cover a tree without drenching it to such an extent that 
the liquid runs down the trunk or drips from the tips of the branches. 
The purpose of this is obvious. To use a familiar illustration, every- 
one has noticed how much more thoroughly a mist or fog will 
dampen the surface of trees, on the under side of the branches as well 
as on the upper side, and how much less thoroughly the surface 
will be wet after a brief but heavy shower. The mist from the noz- 
zles being very fine, it is another obvious fact that only one side of a 
tree can be well sprayed if there is even a moderately strong wind 
blowing. In such a case no effort should be made to spray the side 
away from the wind. Spray with the wind, thoroughly, then watch 
for a day when the wind is from an opposite quarter, and spray the 
other side. 

Spraying Apparatus. 

During the last few years a great many improvements have been 
made in spraying machinery and appliances, and apparatus suitable 



66 



THE SAN JOSE SCALE. 




and efficient for all kinds of work and for small or large plantations 

can now be obtained. 

The pump is, of course, of 
primary importance. The se- 
lection of one depends on the 
use to which it is to be put. 
For small gardens, and where 
onty a few fruit trees or shrubs 
are to be treated, one of the 
various knapsack sprayers, or 
even a bucket pumjj, will serve 
the purpose. For orchard and 
shade tree spraying, a barrel 
pump or compressed air or gas 
sprayer is required; and where 
there is a great deal of w^ork to 

Fig. ll.-Compressed air knapsack sprayer. ^^ ^^^^^ ^^^ j^^.gg commercial 

orchards, or even on park and shade trees, the largest forms of 
the above, or even gasoline or steam power sprayers are, undoubt- 
edly, the most economical. 

The essential points in a pump are that it shall be strong enough 
to give a pressure of from 75 to 100 pounds per square inch; that 
the working parts shall be simple, easily gotten at, and made of bronze, 
so as to work smoothly and resist corrosion as much as possible. 
The pump should have an efficient agitator attached and operated 
by the handle of the pump, or else separately. Large cast-iron cham- 
bers on barrel pumps are undesirable if attached to the top of the 
barrel, as they make them top-heavy and also liable to be caught 
and overturned by overhanging branches. 

For a few bushes or very small trees, the compressed air knap- 
sack shown in Fig. 11 will serve the purpose. This consists of a 
cylindrical air-tight tank of brass or galvanized iron with an air 
pump fixed in the center of it. The tank is filled half or two-thirds full 
with the spray liquid, then closed and a quantity of air is forced 



THE SAN JOSE SCALE. 



67 



in. A pressure sufficient to forcibly eject the liquid can thus be pro- 
duced with one or two pumpings. This form of knapsack is a much 
more desirable apparatus to use than the old style illustrated in Plate 
XIII, Fig. 2, though perhaps less durable. A bucket pump such as that 
illustrated in Plate XII, Fig. 2, can also be made to serve the purpose 
where only a few plants are to be sprayed, but when it becomes 
necessary to move it around, it is inconvenient and time-consuming. 




Fig. 13.— Large tank with agitator, for large tiand or gasolene pump. 

For gardens and small orchards, a small barrel pump such as that 
illustrated in Plate XI makes a very convenient and efficient outfit. 
For larger orchards a barrel pump such as shown in Plate XII, Fig. 1, 
is necessary, and if mounted on cart wheels and provided with suffi- 
cient length of hose, they can be made to do most of the work of 
the small sprayers as well. Such pumps are capable of furnishing 

pressure enough for two leads of 
hose, and can be used under all con- 
ditions where spraying is required. 
For large orchards, hand power tank 
pumps of types indicated in Fig. 13 
and Plate XIII. Fig. 1, are used, and 
furnish an amount of power and ef- 
ficiency excelled only by power spray- 
FiG.i3.-Type of double acting tank ers. As already stated, large gas 
^"'"^' or air pressure or power sprayers 




68 



THE SAN JOSE SCALE. 



are the most convenient for very large orchards and for street and 
park tree spraying in large towns and cities. Plate XII, Fig. 3. 
Gas sprayers are on the market in which carbon dioxide gas 
cylinders, such as used in soda fountains, are utilized. These cyl- 
inders are attached to the air-tight spray tank in such a way that 
the gas can be gradually admitted and a uniform pressure main- 
tained. (See plate XV.) Large air-pressure sprayers are similar, 
except that in place of the gas cylinder a compressed air tank, 
to be filled at a central plant, is carried. 




Fig. 14.— Bamboo extension pipe, 8 to 10 feet long. 




Fig. 15.— Short extension pipe for use with bucket or knapsack 
sprayers. 




Fig. 16.—" Y " for attachins 
two nozzles to one lead 
of hose. 



For the purpose of spraying kerosene or crude 
petroleum, many of the barrel and smaller pumps 
have attachments designed to introduce a given 
quantity of oil into the pump and to combine it 
mechanically with the required amount of water. Such attachments 
are quite effective when in working order, and save the labor of mak- 
ing emulsions, but they can not always be relied on to furnish the 
given proportions of oil and water. The use of emulsified oil is 




^Hfflflni 





Fig. 17.—" Mistry " Ver- 
morel nozzle. 



Pig. 16.—" Mistry Junior ' 
nozzle. 



Fig. 19.— "Demorel' 
nozzle. 



THE SAN JOSE SCALE. 



69 



_o 

o 

x> 

E 
a 



35 



51 



<0 

a 



lll§«?s^ 



CD <y 



cn 




70 



THE SAN JOSE SCALE. 




mm. 




THE SAN JOSE SCALE. 



71 




Wire 
screen 




gospipe 



A - inner box . 
B -outer box. 
C - \A/ire mesh 
D- qaspipe 



Fig. 22.— Home-made Strainers. See page 90. 



72 



THE SAN JOSE SCALE. 



therefore taking the place of mechanical mixtures, and these attach- 
ments are seldom used. 

Hose of good quality, in lengths of thirty-five to fifty feet for each 
lead, should be provided. The short lengths usually furnished with 
spray outfits are of but little use. The half-inch size is amply large 
enough, and some prefer the three-eighths inch size. An extension 
pipe eight to ten feet in length is essential where orchard and shade 
trees are to be sprayed. An ordinary one-fourth inch iron gas pipe 
can be made to serve the purpose. The bamboo extension rod sold 
by dealers is made up of a bamboo pole in which a thin brass pipe 
is inserted. (Fig. 14.) These are very light, and convenient to 
handle, but lack in durability. Whichever form is chosen, it should 
have a brass stop-cock at the lower end so that the spray can be 
turned off at any time. 

The nozzle is a very important part of any spraying outfit. While 
there are a great many types on the market, there are practically 
only two that are extensively used, viz.: the Bordeaux and the 
*Vermorel. The first mentioned type can be made to pro- 
duce a spray graduated from 
a fine, fan-shaped one to a solid 
stream. It is used to some 
extent in spraying tall trees 
when the liquid must be forced 
some distance from the noz- 
zle before it reaches the foliage. 
The Vermorel type gives a 
very fine misty spray. It is produced by forcing 
the liquid, while in a whirling motion, through a 
small orifice in the cap of the nozzle. There are 
a number of forms of this type. The Mistry nozzle, 
represented in Fig. 17, is a recent one made by the 
Gould Manufacturing Company. It has a very large 
eddy chamber into which the liquid is forced in a 
tangential direction, and produces a very fine spray. 





Fig. 24.— a type of Ver- 
morel nozzle without 
plunger. 



Fig. 23.— a recent 
form of Vermorel 
nozzle. 



*See bottom of p. 89 for notes regarding use of term Vermorel. 



THE SAN JOSE SCALE. 



73 



A plunger, held back by a spring, v\-orks through this chamber and 
clears the orifice. The Demorel, made by the Deming Company, is 
of the same general shape, but the whirling motion in the liquid is 
produced by forcing it through a groove which encircles the plunger. 
(Fig. 19.) Another form, see Figs. 23 and 25, now made by the 
Latham & Company, and by Spramotor Company is similar to 
the Demorel in some respects. The whirling of the spray is pro- 
duced by being forced through a groove on the outside of the plun- 
ger, but instead of having 
an elbow and a separate 
plunger, the cap is movable 
and can be forced back on 
the supply pipe to the end 
of which the clearing pin is 
attached. For ordinary 
spraying, the Vermorel type 
is to be preferred. It pro- 
duces a fine, misty spray 
which thoroughly covers 
the twigs and foliage with 
the least amount of waste. 
It is necessary, however, to 
bring the nozzle within 
three or four feet of the foliage in order that the liquid may 
reach it. This can be accomplished by means of extension pipes 
already mentioned, and in addition, for very large trees, b}^ let- 
ting the sprayers climb into the trees, or placing them on elevated 
platforms attached to the spray tank, or by employing ladders. 

With the smaller sizes of nozzles one is not always sufficient to 
produce the volume of spray desired, and in such cases a battery of 
two or more may be used as indicated in Fig. 25, where a number 
of "Spramotor" nozzles are arranged for attachment to one lead of 
hose or by the use of the "y" shown in Fig. 16. 

10 




Fig. 20.— Battery of "Spramotor" Vermorel nozzles 
with drip guard. 



74 THE SAN JOSE SCALE. 

FUMIGATION WITH HYDROCYANIC-ACID GAS. 

As an insecticide this gas was first used by the United States 
Department of Agriculture against the cottony cushion scale on 
citrus trees in California. Later, when the San Jose scale was dis- 
covered in the east, the Department of Agriculture instructed the 
originator of the method, D. W. Coquillet, of the Department, to 
try the effect of the gas on this pest, and it has been gradually de- 
veloped into a very efficient remedy, under certain conditions, not 
only against the scale, but also against a number of other insect 
pests, especially in dwelling-houses, mills, factories, and conserva- 
tories. 

This bulletin being devoted to the San Jose scale, a discussion 
of the use of this gas against other insects is outside its scope. A 
great deal of valuable information is at hand, however, regarding 
its use for other insects, and the writer has applied it in greenhouse 
fumigation at different times with very satisfactory results. Cor- 
respondence regarding such use of the gas will be welcomed and 
carefully attended to at any time. 

The essentials for fumigation are a gas-tight container, or covering,, 
to confine the gas, and potassium cyanide and sulfuric acid with 
which to produce the gas, together with glass or stoneware vessels 
for mixing the chemicals. 

Hydrocyanic-acid gas is formed through the decomposition of 
fused cyanide of potassium (K Cn) under the action of dilute 
sulfuric acid. The reaction is as follows: 
2 K Cn 4- H2 SO4 = 2 H Cn + K^ SO4. 

The H Cn is the Hydrogen cyanide or cyanic-acid, a colorless gas 
with the odor and taste of peach pits. It is a deadly poison to 
human beings as well as to the lower forms of animal life. When 
in water solution this gas becomes a deadly poison known as prussic 
acid. The potassium cyanide from which the gas is made is also a 
deadly poison to animal life. It is, therefore, of the greatest 

IMPORTANCE THAT THE OPERATOR SHOULD USE EXTREME CARE INT 



THE SAN JOSE SCALE. 75 

THE FUMIGATION WORK NOT TO INHALE THE GAS AND TO GUARD 
AGAINST OTHER PERSONS OR DOMESTIC ANIMALS ENTERING THE FUMI- 
GATION HOUSES WHILE THE GAS IS STILL IN THEM. ThE POTASSIUM 
CYANIDE MUST BE KEPT UNDER LOCK AND KEY, AND ESPECIAL CARE 
MUST BE USED NOT TO LET CHILDREN COME NEAR IT. 

The ACID is ordinary commercial sulfm-ic acid of specific gravity 
1.83. It can be secured of dealers in chemicals in almost any large 
city. 

The GENERATORS should be either of stoneware or glass, Ordinary 
one-half or one-gallon crocks serve the purpose admirably. The size 
will depend something on the amount of chemicals to be used in the 
generators. Tall and narrow crocks, provided they are not too 
narrow to admit of the introduction of the cyanide in the paper 
bags, are better than wide ones because the cyanide will be more 
completely covered with the sulfuric acid and water. 

In mixing the chemicals the water should be measured out first; 
_ then measure the sulfuric acid and pour it slowly into the water. 
The presence of the sulfuric acid in the water generates considerable 
heat, and this is desirable to increase the rapidity with which the 
cyanide is dissolved. Do not mix the acid and water, therefore, 
until the fumigation is to be performed. 

When a single paper bag is used to hold the cyanide, the gas begins 
to generate almost immediately after placing the cyanide in the 
liquid. When the gas is first given off, it is accompanied by a steam, 
which is evolved through the great heat occasioned by the chemical 
action. 

It is essential that the operator should lose no time in getting out 
of the room fumigated after all the chemicals have been combined. 
Those who wish to take extra precautions can rig strings by means 
of screw-eyes whereby the cyanide can be lowered into the jars from 
outside the door of the room. If this is done, place the strings and 
bags in position and try them on the jars before mixing the water 
and acid. When everything has been found to work satisfactorily, 
tie up the strings outside the door securely so as to prevent any 



76 THE SAX JOSE SCALE. 

accidental dropping of the cyanide into the jars. Mark the exact 
position of the jars; remove them and put in the water and acid. 
Replace the jars where they stood before, close the door, and release 
the string which drops the cyanide into the generator. 

In purchasing the potassium cyanide, care must be used to secure 
the 98 per cent, pure chemical. Recent chemical analyses in one or 
two of the experiment stations have indicated that some of the 
cyanide sold on the market is only about 50 per cent. pure. It is 
needless to .state that cyanide of this strength will only give about 
half the efficiency which the 98 per cent, cyanide will give, and that 
the formula here stated will not produce the desired results. 

The size of the pieces in which the cyanide comes matters but little, 
if there is sufficient water and acid to cover them thoroughly. 

Orchard Fumigation. 

As an orchard remedy for the San Jose scale it is not of practical 
value in the East, except in the case of particularly valuable trees or 
small trees which can be covered with an especially constructed 
fumigation box, because of the great expense necessary in providing 
the apparatus and in covering and fumigating the trees. 

The first cost of providing tents or a sufficient number of fumiga- 
tion boxes to make the work economical is from SlOO to $300. Ex- 
periments in New York have indicated that the total cost per tree 
of moderate size is from 20 cents to 50 cents. 

Those who wish to use it on small trees can obtain an idea of how 
a practical and convenient apparatus of this kind can be constructed 
from plate XVII, a box which has been devised and used by the New 
York Experiment Station. It has been argued against such boxes 
that they are wasteful of gas because as much must be used for a 
small tree as for a large one. On the other hand, it is much more 
easily set up than a tent would be, and the cubic contents being known, 
definite quantities of gas can be generated. For large trees, tents of 
canvas operated by some form of derrick are necessary. In our 



THE SAN JOSE SCALE. 77 

orchards they are not practical. They wear out quickly, and are too 
expensive and difficult to operate. 

For orchard fumigation, a quantity of cyanide half again as great 
as that recommended on page 78 for fumigating nursery stock must 
be used, because it has been found that the soil, especially if damp, 
will absorb quite a large part of the gas. 

Those wishing to look into this matter should write to the New- 
York and California Experiment Stations for their bulletins. 

Fumigation of Nursery Stock. 

The chief value to the orchardist of this gas comes from the 
possibility of so thoroughly destroying the scale on the nursery 
stock that he has to plant that he can feel assured of freedom from 
the scale so far as his newly planted frees are concerned, and thus 
save the cost of spraying for two or three years. 

Quite a full description of this work was given in the writer's first 
report on nursery inspection, but as this bulletin is to be published 
as separate from the Annual Report of the Board of Agriculture, 
it is perhaps well to repeat the gist of what was given in the above- 
mentioned article. The writer has repeatedly urged, in his reports 
on the nursery inspection work, that the nurserymen should provide 
themselves with adequate fumigation houses or boxes, not only to 
safeguard their customers, but also to treat such stock, cions, and 
grafts as they may themselves purchase, should they have any sus- 
picion that such stock may be infested with the scale. It is becoming 
more and more apparent from year to year that nurserymen can not 
be up to date unless they are in position to apply this valuable remedy 
against the introduction and distribution of certain injurious insects. 
Purchasers of nursery stock can help greatly in emphasizing the need 
of fumigation by demanding that nursery stock about which there 
is the least suspicion that it may have the San Jose scale shall be 
thoroughly fumigated before delivery on their premises. 

The chief arguments against fumigation are, first, that it is expen- 
sive; and secondly, that it is injurious. to the nursery stock. 



78 THE SAN JOSE SCALE. 

The expense consists, of course, first, in providing the necessary box 
or house in which to carry on the fumigation. The cost of these, 
however, should not be prohibitive. The box is of comparatively 
low cost, and the house, while its initial cost is quite large, may 
nevertheless serve useful purposes as storehouse or as workhouse 
during the winter time to such an extent that its cost for fumigation 
purposes is of small account. The cost of chemicals, when bought 
in large quantities, is of comparatively little account. 

There is yet some question as to whether fumigation is injurious 
to nursery stock. It is a common idea among some nurserymen 
that it is the case. Careful experiments in a number of experiment 
stations have not, however, borne out these claims, and it is the 
expressed opinion of many writers that injury is due to carelessness 
in the work. They have indeed found that there has been some loss 
in nursery stock fumigated, but that it is in no case greater than 
would ordinarily occur. 

The advantages of fumigating nursery stock are that it prevents 
further distribution of the scale, and even in infested regions it saves 
spraying for two or three years if the trees are clean when set out. 

APPARATUS, CHEMICALS, AND METHODS OF FUMIGATING NURSERY 

STOCK. 

The essential apparatus for fumigating nursery stock are a gas-tight 
fumigation house or box, one or two earthernware crocks or glass 
jars, an eight or sixteen-ounce graduate for measuring acid and 
water, a set of scales for weighing the cyanide, and a number of small 
paper bags for holding the cyanide. See Plate III, Fig. 2. 

The chemicals are fused potassium cyanide, 98 per cent, pure, and 
commercial sulfuric acid of specific gravity about 1.83. 

The formula is as follows: 

Potassium cyanide, 98 per ceiiu. pure 1 part. 

Commercial sulfuric acid 2 parts. 

Water 4 parts. 



THE SAN JOSE SCALE. 



79 



In a good, tight house, two-tenths of a gram of cyanide should be 
used for each cubic foot of space in the house. If the house is leaky, 
or if it has a dirt floor, 25-100 of a gram should be used. 

The cubic contents of the house and the amount of chemicals to be 
used should be accurately computed. As the quantity of cyanide 
per cubic foot is given in the metric system, and common scales give 
weight in avoirdupois, it is necessary to reduce the total number of 
grams of cyanide to ounces avoirdupois by dividing by .28.35, the 
number of grams in an ounce. To get the quantity of acid and 
water, simply double and quadruple the quantity of cyanide and 
measure both in glass graduate marked according to the avoirchipois 
table. 

Examples: 

To find contents of largest room in fumigation house, pictured in 

Plate XIX. 

Height of front wall 8 feet. 

Height of rear wall 6 feet. 

Width of room 10 feet. 

Length of room 14 feet. 

10 X 6 = 60, or number of sq. ft. in the area of 

rectangle abed. 
10 X 1 = 10, or number of sq. ft. in the area of 
triangle a d f. 

60 4- ^0 = 70, or number of sq. ft. in the area of end. 
70 X 14 = 980 or cu. ft. in contents of room. 
980 X T% = 196, or number of grams potassium cyanide required. 
196 -j- 28.35 = approximately 7, or number of ounces potassium cyanide. 

To find contents of the second largest room in above plan: 

f 6 X 6| ^ 404, or number of sq. ft. in the area of 

rectangle abed. 
6 X f = 3f , or number of sq. ft. in the area of 
triangle a d f. 
40f -f" 3f = 44|, or number of sq. ft. in the area 

of end of room. 
44f X 4 ^ approximately 178, or number of cu. 
ft. in contents of room. 
178 X -/o = 35.6, or number of grams potassium cyanide required. 
35.6 -^ 28.35 = approximately 1|, or number of ounces of potassium cyanide. 





80 THE SAN JOSE SCALE. 

To find contents of fumigation box, pictured in Plate XVIII. 

3 X 83 = 10, or sq. ft. in area of end of box. 
10 X 10 = 100, or cubic ft. in contents. 
100 X 1% := 20, or number of grams potassium cyanide. 
20 -=- 28.35 = approximately f, or ncimberof oances potassium 
cyanide required. 

THE FUMIGATION HOUSE. 

The essential feature in a fumigation house or a box is to have it 
as nearly air-tight as possible. The cheapest construction of walls, 
roof, and floor is double boarding with one or two layers of tar paper 
between. In a house the frame and the first layer of boards should 
be constructed on the box plan, in such a way that strips of the 
paper can be applied beginning at the base of one wall and extending 
up and over the roof to the base of the opposite wall. Let the strips 
lap five or six inches. Projecting rafters or studdings, to get around 
which the paper has to be broken, should be avoided. If such have 
to be used, extra layers of paper should be placed around them so as 
to make the joints air-tight. This precaution, also, should be 
applied to doors and ventilators. It is recommended that two 
layers of paper be used between the boarding all around the building, 
including the roof and floor. The first layer of boards for the wall 
should be matched flooring. The second may be matched or lapped 
siding, placed horizontally, or boards planed on one side with 
weather strips, nailed vertically, as shown in Plate XIX. 

The roof may be shingled, or may be built, like the wall, with 
planed boards and weather strips. 

Partitions should be built in a similar way, but may be constructed 
of a cheaper grade of boards. The floor is constructed in a similar 
manner, placing a fair grade of flooring for the top layer. • 

In order that the gas may have access to all parts of trees to be 
fumigated, the floor should have a movable slat grating on which 
the stock may be laid, and which will hold it a short distance from 
the floor. 



THE SAN JOSE SCALE. 81 

Doors and ventilators should be made similar to those of a refrig- 
erator, and of double boarding, with paper between like the walls. 
Doors should have three, and ventilators two, hinges. They should 
close by means of clamps, like those of a refrigerator. Heavy felt 
strips should be glued to both doors and casing where they come 
together, as shown in section of door, in Plate XIX. 

The plans as drawn may be varied in dimensions to suit each 
individual nurseryman's needs. The plan presented in Plate XIX is 
large enough for the biggest nursery in the State. The house is 
8 feet high in front and 6 feet in the rear, and the larger room contains 
980 cubic feet. At .2 grams per cubic foot this will take 196 grams 
cyanide, or approximately 7 ounces. 

For tender stock this should not be exceeded; but for the bulk of 
fumigation work that a nurseryman has to do, 1 ounce per 100 cubic 
feet is in common use, or 9^ ounces, approximately, for the room 
given. The small room contains 178 cubic feet, which at 2-10 grams 
per cubic foot would take 1^ ounces, and at 1 ounce per 100 cubic 
feet would require l%o ounces cyanide. The small room indicated 
in the plan may be used for storage or workshop. 

Where only small quantities of stock are to be fumigated, a box , 
like that shown in Plate XVIII will serve the purpose very well. It is 
built of double boards, with paper in between. The material for 
the box should be as light as possible, commensurate with sufficient 
strength, so that it can be easily moved about. The demand for 
lightness, strength, and sufficient tightness can be met by constructing 
the inside portion of the box of |-inch material, and reinforcing 
the corners inside with heavier pieces of material to which the boards 
have been nailed. A double layer of tar paper should then be tacked 
on all around the box, and this should be covered with ^-inch matched 
material such as is usually vised in box making. If desired the 
corners can be reinforced on the outside so as to prevent the ripping 
off of the ends of the boards, should they strike against anything 
in moving. The cut will show the plan sufficiently so that a car- 
penter can easily construct it. It contains 100 cubic feet and will 



82 THE SAN JOSE SCALE. 

take approximately 5-7 ounce potassium cyanide, if 2-10 of a gram 
is used per cubic foot, or 1 ounce according to the other plan. 

A few nurserymen have an oiled canvas tent which can be placed 
over a wagon loaded with nursery stock. The edges are weighted 
down and made tight by piling dirt on them. If carefully done, 
fumigation with such apparatus will be efficient; but it is doubtful 
if it is any cheaper in cost or more economical in time than the con- 
struction and use of a fumigation house as already described. A few 
large nurseries in other states have built fumigation houses large 
enough to hold a loaded wagon. Such an arrangement is no doubt 
economical of time, but the cost of house and fumigation is materially 
greater. 

In addition to the house or box the only apparatus needed are one 
or two crocks holding about one-half gallon, an eight-ounce glass 
graduate for measuring acid and water, and some paper bags in 
which to weigh out the cyanide. 

A great many formulas giving the proportion of acid and water 
to cyanide are in use. A common one is to take half again as much 
acid as cyanide, and half again as much water as acid. As the acid 
is quite cheap and the commercial brand is apt to vary in strength, 
a great many use the 1-2-4 formula, or two ounces acid and four 
ounces water to every ounce of cyanide. The cyanide, as already 
noted, should be 98 per cent. pure. The acid may be ordinary com- 
mercial sulfuric, which can be obtained of any druggist or dealer 
in chemicals. 

Of Special Importance. 

In connection with fumigation work of this kind the following 
points should be kept constantly in mind: 

Be sure the potassium cyanide is 98 per cent. pure. 

The potassium cyanide and the gases produced from it are exceed- 
ingly poisonous. The gas must not be inhaled, and the cyanide 
should be kept where children can not get at it. The crocks should 



, THE SAN JOSE SCALE. 83 

be cleaned out after each fumigation and the residue should be buried. 

Fumigate only when trees are in dormant condition. 

The stock should be piled loosely and must not be packed at time 
of fumigation. Every part of the stock, including the roots, should 
be as free from dirt as possible, and especially, of course, the stems 
and branches should be as clean and free as possible from dirt and 
other covering which may prevent the gas from reaching the insects. 

Stock may be fumigated if only slightly damp, but never when wet. 

Never repeat the fumigation of the same stock. 

A strong dose for a short time is less detrimental to the plants and 
more effective against the insects than a weaker dose for a longer 
time. 

Evergreens seldom, if ever, need fumigation. 

Lose no time in getting out and shutting door after cyanide has 
been dropped in acid. 

Fumigation of Peach and Nectarine Houses for tlie San Jose Scale. 

As a remedy for the scale in peach and nectarine houses, the 
experience of the writer during the past two or three years leads 
him to say emphatically that hydrocyanic-acid gas is a very sat- 
isfactory remedy. A number of houses of this kind have been 
fumigated by him or under his direction, and the outcome has been 
beyond expectations. One of the first was that of Mr. Philip Caswell, 
of Newport, and the following letter from him will indicate the 
results that he has had: 

Newport, R. I., January 10th, 1908. 

Mr. a. E. Stene, 

R. I. Agricultural College, 

Kingston, R. I. 

Dear Sir: — In reply to your favor of the 3rd inst., would say that the trees 
in my peach house were young stock and had not borne fruit over two seasons 



84 THE SAN JOSE SCALE. 

before you fumigated the house the first time. I don't think that the stock was 
infected when I imported it from England, as there had been scale on the old 
trees. The young stock, however, seemed to take it pretty badly, so that it 
showed its effects on the fruit the year previous to the fumigation. 

The results of the first application of the potassium cyanide mixture were 
quick to be seen, apparently killing most of the scale. However, we gave the 
house another fumigation in about two weeks, which made all scale life extinct. 
Much improvement was noticed in the fruit that summer. 

As a matter of precaution we now use the treatment every spring, just before 
the trees break, which keeps them free from the scale. I am inclined to believe 
that no preparation could work better than this cyanide mixture on peach trees 
inside a house. 

Very respectfully yours, 

PHILIP CASWELL. 

It should be noted that, according to his letter, he himself gave 
the house a second fumigation a short time after the first, but this 
is not to be recommended. It is the experience of most users of the 
gas that two fumigations following closely upon each other are 
detrimental, and the results which the writer has had with other 
houses where only one fumigation has been given indicate that one 
each season is amply sufficient to keep the houses entirely free of the 
scale. In fact, if surroundings are such that the scale is not carried 
into the house from infested trees or shrubs outside, there should be 
no occasion to fumigate after the house has been thoroughly treated 
two or three successive years. 

DIRECTIONS FOR FUMIGATING PEACH AND NECTARINE HOUSE. 

The first essential is to determine accurately the contents, in 
cubic feet, of the house. The methods differ a little with the different 
kinds of houses. With an even span house, such as shown in Fig. 26, 
get the width of the house from A to C; the height of the wall from 
A to B; and the distance from the floor to the pitch from D to E; 
and finally, the length of the house. 

If now we find the area of one end of the house in square feet and 



THE SAN JOSE SCALE. 



85 



multiply this number by the number expressing the length of the 
house in linear feet, we shall obtain the contents in cubic feet. 

Supposing the width of the house figured is 20 feet; the height of 
each wall 5 feet; and the height from the floor to the peak 10 feet; 
and the length 100 feet. The contents are ascertained by the fol- 
lowing method: 

20 X 5 = 100, or number 
of sq. ft. in area of rect- 
angle F B A C. 
20 X 2i = 50, or number 
of sq. ft. in area of triangle 
FEB. 
100 ft. + 50 = 150, or num- 
ber of sq. ft. in area of end. 
150 X 100 = 15,000, or 
number of cubic ft. in 
contents of house. 




Fig. 26. 



If the house is a lean-to, as shown in the next illustration, Fig. 27, 
we must ascertain the height from A to B; the width from A to C; 
and the height from C to F, to find the area of one end of the house. 
After this is found, the example is the same as in the previous 
illustration, as follows: 



20 X 5 = 100, or area in sq. 

ft. of rectangle F D A C. 
20 X 2J =^ 50, or area in sq. 
ft. of triangle FB D. 
100 + 50 = 150, or area of 

end in sq ft. 
150 X 100= 15,000, or cubic 
ft. in contents of house. 




Fig. 27. 



If the house is an uneven span as shown in the third illustration, 
Fig. 28, the example becomes a little more complicated. We have 
to have the height of both walls from A to B, and from C to F; the 
distance from A to D and from D to C; and the height from D to E. 
This will enable us to divide off the end of the house into two rec- 



86 



THE SAN JOSE SCALE. 



tangles and two triangles; then by finding the area of each one of 
these, separately, and adding the results together, we will have the 
area of the end of the house. 



'p,=:rr::rr7 — .:— -Jh 



15 X 5 = 75, or number 
of sq. feet in the area of 
rectangle F M D C. 
15 X 2J = 37§, or number 
of sq. ft. in the area of 
triangle F M E. 
5 X 8 = 40, or number of 
sq. ft. in the area of rec- 
FiG. 28. tangle N B A D. 

5 X 1 =: 5, or number of sq, ft. in the area of triangle B N E. 
75 -|- 37i + 40 -[- 5 = 157J, or number of sq. ft. in the area of one end of 
the house. 
157J X 100 = 15,750, or number of cubic ft. in the contents of the house. 

After finding the contents of the house in cubic feet, the method 
of ascertaining the amount of chemicals is the same as that already 
given for fumigating nursery stock. 



THE- OPERATION. 

The chemicals secured, select a night when there, is little or no 
wind, and, having previously closed up the house so far as possible, 
arrange one or two ventilators so that they can be opened from the 
outside. Close all other openings excepting one door. 

If the house is a long one, two or more jars should be used, and 
the total quantity of chemicals divided accordingly. 

Arrange the jars by suspending the cyanide over them with string, 
as already described, or, dispensing with this, which is perfectly safe 
if one uses ordinary care, place a bag beside each jar. Now turn the 
hose on the outside of the house so as to wet it down thoroughly. 
This will close up the openings in the glass of the roof to a considerable 
extent. Begin at the jar farthest away from the door and dropping 
the cyanide into it pass quickly to the next, and so on until the door 



THE SAN JOSE SCALE. 



87 



is reached. Close and lock the door and wait the required length of 
time, which need not exceed one hour, then open the doors and 
ventilators and ventilate the house for a half hour or so before 
entering. 

Usually one can allow a peach house to remain closed until the 
following morning. Most of the gas will have leaked out by that 
time, and with a little precaution of opening doors and ventilators 
for a short time before going in, anyone can enter and open up the 
house fully. After a half-hour's ventilation, it should be perfectly 
safe for anybody to work in. 



Dipping Nursery Stoclc. 




Dipping Body Only 

OF 

Nursery Trees 



Scale Destroyer, 

a H — fr 



and less harmful to the 
nursery stock. 

For dipping, nursery 
stock should be tied in 
loose bundles. It may be 
immersed, ^tem and top 
only, or the whole bundle 
roots and all, may be put 
into the dipping solution- 

Trees should be care- 
fully pruned before dip- 



There has been con- 
siderable discussion in 
some. of the agricultural 
papers about the advis- 
ability of dipping nursery 
stock, either at the nur- 
sery or at the place where 
it is to be planted. It is 
claimed for this method 
that it is considerably 
cheaper than fumigation 




Fig. 30. 



88 THE SAN JOSE SCALE. 

ping and should remain in the solution for only a short time, say^. 
one to two minutes. 

The solution may be either the standard lime-sulfur wash, in some- 
what greater strength perhaps than that ordinarily used for orchard 
trees, or one of the soluble oils. 

The accompanying illustrations, Figs. 29 and 30, indicate clearly 
enough the apparatus needed and the method of doing the work. 

There has not been enough work done on this by careful and un- 
biased experimenters to unqualifiedly recommend it, but evidence 
seems to point to the fact that it is of considerable value and should 
be recommended for trial by orchardists and for further work by 
experiment stations. 



THE SAN JOSE SCALE. 89 



Additional Notes and Explanations Regarding Illustrations. 



ACKNOWLEDGMENTS FOR USE OF CUTS. 

The writer is indebted to the United States Department of Agri- 
culture for cuts for Figs. 3, 5, 6, 8, and 9. 

To the Virginia Crop Pest Commission for cuts for Figs. 1, 2, and 7, 
and Plate IX. 

To the New York (Geneva) Experiment Station for cuts for Plate 
III, Fig. 1, and for Plate XVII. 

To the Connecticut Experiment Station for cuts for Plate III, 
Fig. 2, and Plate XVI, Fig. 2. 

To the Rhode Island Experiment Station for cut for Plate V. 

To the American Horticultural Distributing Co. for cuts for Figs. 
29 and 30. 

To the Delaware Experiment Station for cut for Plate II. 

To R. I. Smith, State Entomologist, Atlanta, Ga., for cut for Plate 
XVI, Fig. 1. 

To the Wallace Machinery Co. for cuts for XIV, Figs. 1 and 2. 

To the Gould Mfg. Co. for cuts for Plate XII, Figs. 1, 2, and 3; 
Plate XIII, Figs. 1, 3, and 4; and Figs. 10, 12, 14, 17, and 18. 

To the Friend Mfg. Co. for cuts for Figs. 13 and 24. 

To the Niagara Sprayer Co. for cut for Plate XV. 

To the Field Force Pump Co. for cut for Fig. 11. 

To the Deming Co. for cuts for Fig. 19, and Plate XIII, Fig. 2. 

To the Latham Co. for cut for Fig. 23. 

To the Morrill and Morley Co. for cut for Plate XL 

To the Spramotor Co. for cut for Fig. 25. 

All other illustrations are original. 

NOTES. 

Nozzles. — The term " Vermorel," as the name of a type, is here 
used for all nozzles in which the liquid is forced through the orifice 



90 THE SAN JOSE SCALE. 

of the nozzle while in a whirling motion, produced either by injection 
of stream into an eddy chamber in a tangential direction, or by 
spiral grooves. Older terms are Cyclone nozzles or Eddy Chamber 
nozzles. 

Figures 18 and 24 indicate the latest forms of Vermorel nozzles. 
These have comparatively large eddy chambers, and apertures large 
enough to permit the passage of all particles which can go through 
the strainer of the pump. They do away with the plunger of the old- 
style Vermorel, which was designed for cleaning the orifice should it 
clog up. 

Apparatus for Boiling the Lime-Sulfur Wash. — Figures 20 
and 21 and Figures 1 and 2, Plate XVI, indicate methods of arranging 
apparatus for boiling the lime-sulfur wash. No further explanation 
is necessary except to emphasize that when the barrels are arranged 
on a platform this should be high enough, or arranged on a side-hill 
in such a way that the prepared wash can be run into the spray 
barrels by gravity. 

Strainers. — Figure 22 indicates how home-made strainers may be 
constructed which will give as good results as that shown in Figure 
10, though somewhat more cumbersome. The one at the top is made by 
tacking brass wire strainer cloth on a slant inside a common pail into the 
bottom of which a small piece of gaspipe has been inserted. The one 
illustrated below consists of an outer box about one foot square and 
ten inches deep, outside measurement, and a removable inner box- 
like frame so constructed that the strainer cloth forms a slanting 
bottom in it. A gaspipe forms an outlet as above. This form can 
be more easily cleaned than the pail. 

Plate IV. — The cuts in this plate are from photographs taken in 
Mr. N. S. Winsor's orchard, Greenville. Figure 1 shows the ex- 
cellent culture results attained by pasturing hogs in the orchard, 
and Figure 2 illustrates a good cover crop of rye in a pear orchard. 
In clean-culture method of orcharding, cultivation should cease 
during the first part of August and a cover crop should be sown. 



THE SAN JOSE SCALE. 91 

Rye is excellent in many ways, but it is better to use a leguminous 
crop which will gather atmospheric nitrogen as well as hold the soil 
to prevent washing, and furnish humus. 

Plate V. — This illustration is more or less typical of neglected 
apple trees in our State. The moss and lichens form an excellent 
harboring place for insects and plant diseases. The trees can be 
readily cleaned by the application of Bordeaux mixture or the lime- 
sulfur wash. 

Plate VI. — The types of trees shown are characteristic. Close 
planting and misdirected pruning result in the first type, in which 
picking, as well as spraying and pruning, is laborious and expensive. 
The type shown in the lower picture, although not ideal, is a far better 
form and should be adopted by orchardists in the future. 

Plate VII. — This picture explains itself. The natural tendency 
of most varieties of pears to assume a columnar shape has been 
accentuated by the pruning and environment of this tree, and the 
result is undesirable from the standpoint of economy in pruning, 
spraying, and harvesting. 

Plate VIII. — This picture is from a photo taken in the orchard 
of Rev. Mr. Hawkins, East Greenwich. It illustrates the method 
of thorough pruning and careful spraying necessitated by badly 
infested trees. 




Plate II. 

(a) Kieffer pears badly infested with the San Jose Scale; (b) Duchess pear affected with 

Pear Leaf Blinht (EntonidSporium niaculatum)-See pagre 23; (c) Peach leaves showing 

scales along the veins; (d) The underside of adult female scale, also the insect without 

the scale covering. From Bui. 58, Del. Exp. Sta. 




Fig. 1.— Picture of Scale on Bark slightly enlarged. After N. Y. (Geneva) Station. 
For explanation see page 25. 




Fig. 2.— Fumigation Utensils. After Britton, Conn. Exp. Sta 

For explanation see page 78. 

Pl.\te III. 




Fig. 1. 




Fig. 2. 

Plate IV. 

Good culture in Apple and Pear Orchards. For explanation see pages 42, 43 and 90. 




Plate VI.— High and low training of apple trees. See pages 42. 43 and 91. 




Plate VII.— Tall pear trees on which the scale must be fou^'lit at a great disadvantage. 
See pages 4i, 43 and.91. 



^ CD 

o — 
5 vi 



O D. 

B o 

2. !» 



SJ 



9 < 



5^- 





Plate X.— Peach tree badly infested with San Jose Scale cut back and renewed. 
With continued thorough spraying and a little pruning this tree would make a good 
bearing. tree. Others shown in tlie backgrounds were so low in vitality wheiv 
treated tliat they failed to revive. 




Plate XL— Small portable barrel pump. See page ^67. 





Fig. 2.— Bucket pump. 



FIG. 1.— Barrel pump showing agitator. 




Fig. 3— Gasolene power sprayer. 

Plate XII. 

For explanation and discussion see pages 67 and ' 





Fig. 3.— Knapsack Spray Pump. 
Deming Co. 



Fig. 1.— Vice- Admiral tank pump. 











■mmMWf ' 




/s 




■ -,..__ -^ . 




Fig. 3. — Gasolene power sprayer 
mounted on tank with tower. 



Fig. 4.— Gasolene power>prayer in operation. 



Plate. 'XII. 
For explanation and discussion see pages 66 to 73. 




Fig 1 -Invincible Mounted Sprayer- Wallace Machinery Co. 
The spray liquid is pumped into an airtight tank together with 
compreLd air by pumps driven from the wheels. When machme is 
standing still.the compressed air continues the work. 




Fig. S.-Gasolene power sprayer with air cooled engine. 
Plate XlV. 




Plate XV. 
Niagara Gas Sprayer with Tower. Note the carbon dioxide gas- 
cylinder from which power to force liquid out of large tank is de- 
rived. See page 68. 




Fig. 1.— Plant for preparing lime sulfur wai-h with steam. 




F(G. 3. — Cooking lime-siilfur wash with steam. 

Plate XVI. 

For explanation see page 51. 




Plate XVII.— Hexagonal Fumigator for trees. This fumigator is made in sections and is taken, 
apart in moving. For explanation see page 76. 



CO 



w > 



» B 



w' (IB ?— ; 



P'S - 






§ » s 

CO 00 tr 



S' ° 









^ 25 

B r 



CO ^ £, 

^ 00 g * 




f 



"^""I'f^^'^m 



i^^ 




CI) 

O 

J 

H 

Z 



4'x4-' 



4-x6' 







3^ 



TT 



VkNTlU/VTOR S'x4-' 



10 xlV 



Ventilator <S'x<2>' 



Jl 



^ 



"Door 4-'x65 






'/ Felt, 



Section or Door 



Platk XIX. 
For description see pages 80 and 61. 



LIBRARY OF CONGRESS 




000 889 003 1 



1 



E. L. FREEMAN COMPANV 

STATE PRINTERS 

PROVIDENCE , R. I. 



